USPS Stamp Weight Calculator
Calculate accurate postage costs based on weight.
Postage Cost Calculator
Enter the details of your mailpiece to estimate the postage cost.
Standard Letter
Large Envelope (Flat)
Small Package
Select the type of item you are mailing.
Enter weight in ounces (oz). For letters, the first ounce is the most critical.
For packages and large envelopes. Max length for First-Class Package Service is 22 inches. Max for other services can be larger.
For packages and large envelopes. Max width for First-Class Package Service is 15 inches.
For packages and large envelopes. Max height for First-Class Package Service is 12 inches.
Zone 1
Zone 2
Zone 3
Zone 4
Zone 5
Zone 6
Zone 7
Zone 8
Enter the USPS destination zone (for packages and some mail classes). Local is Zone 1.
Estimated Postage Cost
$0.00
First Ounce Cost: $0.00
Additional Ounce Cost: $0.00
Dimensional Weight (lbs): 0.00
Postage Type: N/A
Postage is calculated based on mailpiece type, weight, dimensions (for packages), and destination zone. Standard letters have a base rate for the first ounce and an additional cost for each subsequent ounce. Packages use different pricing structures, often influenced by weight, dimensions, and distance (zones).
Cost vs. Weight Projection (Standard Letter)
Cost by Destination Zone (1 lb Package)
USPS Pricing Tiers (Example for Standard Letters)
| Weight (oz) | Price (First-Class Mail) |
|---|---|
| 0 – 1 | $0.68 |
| 1 – 2 | $0.92 |
| 2 – 3 | $1.16 |
| 3 – 4 | $1.40 |
| 4 – 5 | $1.64 |
| 5 – 10 | $2.08 |
| 10 – 12 | $2.32 |
| 12 – 13 | $2.56 |
| 13 – 15.5 | $2.80 |
| 15.5 – 16 | $3.04 |
USPS Stamp Weight Calculator: Your Guide to Accurate Postage
Understanding how much postage you need is crucial for sending mail and packages efficiently. The United States Postal Service (USPS) has a complex pricing structure that depends on various factors, including the weight of your item. A USPS stamp weight calculator is an invaluable tool for anyone sending mail, helping to avoid underpayment or overpayment of postage. This guide will delve into what a USPS stamp weight calculator is, how it works, and how to use it effectively, along with practical examples and key factors affecting USPS postage costs.
What is a USPS Stamp Weight Calculator?
A USPS stamp weight calculator is an online tool designed to estimate the cost of sending mail or packages through the USPS based primarily on the item's weight. It simplifies the process of determining the correct amount of postage needed by taking user-inputted information—like the type of mailpiece and its weight—and applying USPS's official pricing rules to provide an estimated cost. This is particularly helpful for standard letters, large envelopes (flats), and even small packages, where the weight is a primary determinant of postage cost. For businesses and individuals who frequently mail items, using a USPS stamp weight calculator can save both time and money. It's a vital resource for ensuring compliance with USPS regulations and avoiding the delays or extra fees associated with incorrect postage. It helps answer the common question: "How much postage do I need?"
Who should use it:
- Individuals sending personal letters or cards.
- Small businesses mailing invoices, marketing materials, or products.
- E-commerce sellers shipping orders.
- Anyone unfamiliar with current USPS postage rates.
Common misconceptions:
- "A stamp is always 68 cents." While the current price for a First-Class Mail Forever stamp covers the first ounce of a standard letter, anything heavier requires additional postage.
- "All packages cost the same." Package pricing is highly variable, depending on weight, size, destination, and service type.
- "Weight is the only factor." For packages and large envelopes, dimensions and shape also play a significant role in determining costs.
USPS Stamp Weight Calculator: Formula and Mathematical Explanation
The core logic behind a USPS stamp weight calculator involves referencing and applying USPS's official rate charts, which are updated periodically. The calculation isn't a single, simple formula but rather a series of conditional checks and lookups based on mailpiece characteristics. For the most common item, the standard letter, the calculation often follows this pattern:
1. Determine Base Cost: The calculator checks if the item is a standard letter. If so, it applies the rate for the first ounce. For current First-Class Mail letter rates, this is often covered by a standard Forever Stamp.
2. Calculate Additional Ounce Cost: For each ounce *exceeding* the first ounce, an additional cost is added. This is a fixed increment per additional ounce, up to a certain weight limit for letters (typically 3.5 ounces).
3. Handle Different Mail Classes: If the item is a large envelope (flat) or a package, the calculator switches to different rate tables. These tables consider weight, dimensions, and destination zone more heavily.
4. Dimensional Weight (Packages): For larger packages, USPS may calculate "dimensional weight" (also known as DIM weight). This is based on the package's volume (Length x Width x Height divided by a cubic factor, e.g., 166 for USPS Retail Ground). If the dimensional weight is greater than the actual weight, the postage is calculated based on the dimensional weight.
Formula (Simplified for Standard Letters):
Postage Cost = Base Rate (First Ounce) + (Additional Ounce Rate * Number of Additional Ounces)
Where:
Base Rate (First Ounce): The cost for the first ounce or fraction thereof.Additional Ounce Rate: The cost for each ounce or fraction thereof *after* the first ounce.Number of Additional Ounces: Calculated asCeiling(Weight in Ounces) - 1, ensuring any fraction of an ounce over the first counts as a full additional ounce.
Variables Table:
| Variable | Meaning | Unit | Typical Range |
|---|---|---|---|
| Weight | The total weight of the mailpiece. | Ounces (oz) or Pounds (lbs) | Letters: 0.1 – 3.5 oz Large Envelopes: 1 oz – 3.5 oz Packages: 1 oz – 70 lbs |
| Length | The longest side of the mailpiece. | Inches (in) | Packages: Up to 108 inches combined (L+Girth) Letter: ~6.125 in max |
| Width | The second longest side of the mailpiece. | Inches (in) | Packages: Up to 15-22 in (service dependent) Letter: ~11.5 in max |
| Height (Thickness) | The shortest side of the mailpiece. | Inches (in) | Packages: Up to 12 in (service dependent) |
| Destination Zone | The calculated distance between the origin and destination ZIP codes. | Zone Number (1-8) | 1 (local) to 8 (farthest) |
| Mailpiece Type | Classification of the item being mailed (Letter, Flat, Package). | Category | Letter, Large Envelope, Package |
| Dimensional Weight Factor | USPS divisor to calculate dimensional weight. | None | Typically 166 for USPS Retail Ground, 139 for Priority Mail/Express Mail if volume is over 1 cubic foot. |
Practical Examples (Real-World Use Cases)
Let's illustrate how the USPS stamp weight calculator works with concrete examples:
Example 1: Sending a Birthday Card
Scenario: You're mailing a standard-sized birthday card with a standard envelope. The card and envelope together weigh 1.5 ounces.
- Inputs:
- Mailpiece Type: Standard Letter
- Weight: 1.5 oz
- Dimensions: Not applicable for standard letters
- Calculation Steps:
- The calculator identifies this as a standard letter.
- The first ounce costs $0.68 (current First-Class Mail rate).
- There is 0.5 oz additional weight. This counts as one additional ounce.
- The additional ounce cost is $0.24 (current First-Class Mail rate).
- Total cost = $0.68 (first oz) + $0.24 (second oz) = $0.92.
- Outputs:
- Primary Result: $0.92
- First Ounce Cost: $0.68
- Additional Ounce Cost: $0.24
- Postage Type: First-Class Mail Letter
- Interpretation: You would need $0.92 in postage. This means one Forever stamp ($0.68) plus $0.24 in additional postage, perhaps using a combination of stamps or a meter strip.
Example 2: Shipping a Small Product
Scenario: You are shipping a small, lightweight item (e.g., a piece of jewelry) in a small box. The box weighs 4 ounces. Its dimensions are Length: 8 inches, Width: 6 inches, Height: 3 inches. The destination is Zone 5.
- Inputs:
- Mailpiece Type: Small Package
- Weight: 4 oz (0.25 lbs)
- Length: 8 in
- Width: 6 in
- Height: 3 in
- Destination Zone: Zone 5
- Calculation Steps:
- The calculator identifies this as a package.
- Calculate Dimensional Weight: (8 * 6 * 3) / 166 = 144 / 166 ≈ 0.87 lbs.
- Compare Actual Weight (0.25 lbs) vs. Dimensional Weight (0.87 lbs). Since DIM weight is greater, postage will be based on 0.87 lbs (rounded up to 1 lb for pricing).
- Look up the rate for a 1 lb package going to Zone 5 using the appropriate service (e.g., USPS Ground Advantage). Let's assume for this example, the rate is $7.50.
- Outputs:
- Primary Result: $7.50
- Dimensional Weight (lbs): 0.87 (priced as 1 lb)
- Postage Type: USPS Ground Advantage (example)
- Destination Zone: Zone 5
- Interpretation: The cost to ship this small package is estimated at $7.50, primarily determined by its dimensional weight and destination zone, rather than its actual light weight.
How to Use This USPS Stamp Weight Calculator
Using our USPS stamp weight calculator is straightforward. Follow these steps:
- Select Mailpiece Type: Choose 'Standard Letter', 'Large Envelope (Flat)', or 'Small Package' from the dropdown menu. This tells the calculator which pricing rules to apply.
- Enter Weight: Input the weight of your item in ounces (oz) into the 'Weight' field. Be as accurate as possible, as this is a primary cost factor.
- Input Dimensions (If Applicable): If you selected 'Large Envelope' or 'Small Package', you'll need to enter the Length, Width, and Height in inches. Ensure you measure the longest, second longest, and shortest sides, respectively.
- Select Destination Zone (If Applicable): For packages, select the appropriate USPS destination zone. You can find this information using online USPS zone calculators based on ZIP codes.
- Click 'Calculate Postage': The tool will instantly display the estimated postage cost.
How to read results:
- Primary Highlighted Result: This is the total estimated postage cost.
- Intermediate Values: These show key components like the cost of the first ounce, additional ounce costs, and dimensional weight calculations, offering transparency.
- Postage Type: Indicates the likely service class (e.g., First-Class Mail Letter, USPS Ground Advantage).
Decision-making guidance: The estimated cost helps you decide if the postage is reasonable for the item you're sending. If the cost seems high, consider if a lighter packaging material or a different shipping service might be more economical. For packages, understanding dimensional weight can prompt you to use smaller boxes.
Key Factors That Affect USPS Postage Costs
Several factors influence the final postage cost, going beyond just the weight:
- Weight: As demonstrated, this is often the primary driver. Heavier items cost more to ship. The USPS has different weight tiers and limits for various mail classes.
- Dimensions (Size): For packages and large envelopes, Length, Width, and Height are critical. USPS uses these to calculate dimensional weight and also has size restrictions (e.g., maximum length + girth). Oversized items incur significant surcharges.
- Destination Zone: Postage costs for packages increase with distance. Shipping across the country (higher zones) costs more than shipping locally (lower zones). USPS calculates zones based on the distance between the origin and destination ZIP codes.
- Mailpiece Type & Service Level: A standard letter has different pricing than a large envelope (flat) or a package. Furthermore, service levels like First-Class Mail, Priority Mail, Priority Mail Express, and USPS Ground Advantage offer different delivery speeds and prices. Faster services cost more.
- Shape and Contents: Irregularly shaped items, items requiring special handling (like hazardous materials), or fragile contents might incur additional fees or require specific packaging. Letters must be flexible; rigid items are treated as packages.
- USPS Rate Updates: Postage rates are subject to change, typically annually. A calculator should be updated to reflect the latest USPS pricing to remain accurate. Relying on outdated information can lead to incorrect postage calculations.
- Additional Services: Extras like Certified Mail, Return Receipt, Insurance, or Signature Confirmation add to the base postage cost but provide tracking and proof of delivery.
- Fuel Surcharges: While less common now for USPS retail, fuel costs can indirectly influence overall postal service operating costs and subsequent rate adjustments.
Frequently Asked Questions (FAQ)
What is the current price of a USPS Forever stamp?
As of early 2024, a USPS Forever stamp for First-Class Mail letters costs $0.68. However, this price only covers the first ounce. Additional ounces for letters cost extra.
How much does it cost to mail a 2 oz letter?
A 2 oz letter costs the price of the first ounce ($0.68) plus the price for one additional ounce ($0.24), totaling $0.92.
What if my letter is slightly over 3.5 ounces?
If your letter exceeds 3.5 ounces, it cannot be mailed as a First-Class Mail letter and must be sent as a First-Class Mail Flat (large envelope) or a package, with significantly higher costs.
How does USPS determine package dimensions?
Length is the longest side. Width is the second longest. Height (or thickness) is the shortest side. For calculating postage, Length + Girth (distance around the package perpendicular to the length) is often used, especially for larger parcels.
What is Girth?
Girth is the distance around the thickest part of the item, perpendicular to its length. It's calculated as 2 * (Width + Height).
How do I find my destination zone?
You can find your destination zone using the USPS online Zone Calculator on the USPS website by entering the origin and destination ZIP codes.
Can I use this calculator for international mail?
No, this calculator is designed for domestic USPS mail within the United States. International postage rates are calculated differently and depend on the destination country, weight, and service selected.
What happens if I put the wrong postage on my mail?
If the postage is insufficient, the item may be returned to the sender, delayed while the recipient pays the postage due, or rejected altogether, depending on the service and amount of underpayment.
Does the calculator account for the 'cubic pricing' option for packages?
This calculator provides estimates based on standard weight and dimensional factors for common services like USPS Ground Advantage. Cubic pricing applies to specific scenarios (e.g., small, heavy items shipped via Priority Mail) and may require specialized calculators or direct consultation with USPS.
Related Tools and Internal Resources
To further assist with your shipping needs, explore these helpful resources:
- USPS Stamp Weight Calculator: Our main tool for estimating postage costs.
- USPS Pricing Tiers: Understand the cost structure for different weights.
- Guide to Using the Calculator: Step-by-step instructions for accurate results.
- Real-World Shipping Examples: See how different mailpieces are costed.
- USPS Zone Calculator Guide: Learn how to determine your destination zone.
- Guide to Measuring Package Dimensions: Ensure accurate measurements for accurate quotes.
- USPS Service Comparison: Choose the best shipping speed and price.
- Tips for Cost-Effective Mailing: Save money on your shipments.
Results copied to clipboard!
var baseLetterRate = 0.68; // Current rate for the first ounce of a letter
var additionalOunceRate = 0.24; // Current rate for each additional ounce of a letter
var letterMaxWeightOz = 3.5; // Max weight for a standard letter in ounces
var packageDimWeightFactor = 166; // Default factor for dimensional weight
function validateInput(inputId, fieldName, minValue, maxValue) {
var input = document.getElementById(inputId);
var errorDiv = document.getElementById(inputId + 'Error');
var value = parseFloat(input.value);
errorDiv.textContent = "; // Clear previous error
if (isNaN(value)) {
if (input.value !== ") { // Allow empty to be cleared, but not if it's a non-number
errorDiv.textContent = fieldName + ' must be a number.';
}
input.value = "; // Clear invalid input
return false;
}
if (value maxValue) {
errorDiv.textContent = fieldName + ' is too high. Max allowed is ' + maxValue + '.';
// Decide whether to clear or cap – capping might be better for user experience
// input.value = maxValue;
return false;
}
return true;
}
function getPricingData() {
// Mock data for pricing. In a real scenario, this would be fetched or stored more robustly.
// For standard letters (First-Class Mail)
return {
letter: {
firstOunce: 0.68,
additionalOunce: 0.24,
maxWeight: 3.5,
tiers: [
{ weight_max: 1, price: 0.68 },
{ weight_max: 2, price: 0.92 },
{ weight_max: 3, price: 1.16 },
{ weight_max: 3.5, price: 1.40 }, // Typically up to 3.5oz for letters
]
},
largeEnvelope: { // Flats
firstOunce: 1.35, // Example rate for Flats
additionalOunce: 0.24, // Example rate for Flats
maxWeight: 13, // Max for Flats is typically 13 oz for First Class
tiers: [
{ weight_max: 1, price: 1.35 },
{ weight_max: 2, price: 1.59 },
{ weight_max: 3, price: 1.83 },
{ weight_max: 4, price: 2.07 },
{ weight_max: 5, price: 2.31 },
{ weight_max: 6, price: 2.55 },
{ weight_max: 7, price: 2.79 },
{ weight_max: 8, price: 3.03 },
{ weight_max: 9, price: 3.27 },
{ weight_max: 10, price: 3.51 },
{ weight_max: 11, price: 3.75 },
{ weight_max: 12, price: 3.99 },
{ weight_max: 13, price: 4.23 },
]
},
// Package rates are highly variable (service, zone, weight, dim weight)
// This is a simplified placeholder logic
package: {
// Placeholder rates – actual USPS rates are complex and zone-dependent
// This function will simulate a lookup based on weight and zone
getRate: function(weightLbs, zone) {
// Extremely simplified lookup. Real USPS rates are based on specific weight breaks per zone.
var rates = {
'1': [0, 5.50, 5.75, 6.00, 6.25, 6.50, 6.75, 7.00, 7.25], // Zone 1-8 rates for 1 lb
'2': [0, 5.75, 6.00, 6.25, 6.50, 6.75, 7.00, 7.25, 7.50], // Zone 1-8 rates for 2 lbs
'3': [0, 6.00, 6.25, 6.50, 6.75, 7.00, 7.25, 7.50, 7.75], // Zone 1-8 rates for 3 lbs
'4': [0, 6.25, 6.50, 6.75, 7.00, 7.25, 7.50, 7.75, 8.00], // Zone 1-8 rates for 4 lbs
'5': [0, 6.50, 6.75, 7.00, 7.25, 7.50, 7.75, 8.00, 8.25], // Zone 1-8 rates for 5 lbs
'6': [0, 6.75, 7.00, 7.25, 7.50, 7.75, 8.00, 8.25, 8.50], // Zone 1-8 rates for 6 lbs
'7': [0, 7.00, 7.25, 7.50, 7.75, 8.00, 8.25, 8.50, 8.75], // Zone 1-8 rates for 7 lbs
'8': [0, 7.25, 7.50, 7.75, 8.00, 8.25, 8.50, 8.75, 9.00] // Zone 1-8 rates for 8 lbs
};
// Approximate weight bracket
var weightBracket = Math.min(Math.ceil(weightLbs), 8);
var zoneIndex = parseInt(zone);
if (rates[weightBracket] && rates[weightBracket][zoneIndex] !== undefined) {
return rates[weightBracket][zoneIndex];
}
return 15.00; // Default high price if lookup fails
}
}
};
}
function updatePricingTable() {
var pricingTableBody = document.getElementById('pricingTableBody');
pricingTableBody.innerHTML = "; // Clear existing rows
var pricingData = getPricingData();
var mailpieceType = document.getElementById('mailpieceType').value;
if (mailpieceType === 'letter') {
var tiers = pricingData.letter.tiers;
tiers.forEach(function(tier) {
var row = pricingTableBody.insertRow();
var cellWeight = row.insertCell(0);
var cellPrice = row.insertCell(1);
cellWeight.textContent = tier.weight_max === 1 ? 'Up to 1 oz' : (tier.weight_max === 3.5 ? 'Up to 3.5 oz' : 'Up to ' + tier.weight_max + ' oz');
cellPrice.textContent = '$' + tier.price.toFixed(2);
});
} else if (mailpieceType === 'largeEnvelope') {
var tiers = pricingData.largeEnvelope.tiers;
tiers.forEach(function(tier) {
var row = pricingTableBody.insertRow();
var cellWeight = row.insertCell(0);
var cellPrice = row.insertCell(1);
cellWeight.textContent = 'Up to ' + tier.weight_max + ' oz';
cellPrice.textContent = '$' + tier.price.toFixed(2);
});
} else {
// For packages, a table isn't as straightforward as it depends on zones.
// We can show a generic example or a range.
var row = pricingTableBody.insertRow();
var cellWeight = row.insertCell(0);
var cellPrice = row.insertCell(1);
cellWeight.textContent = 'Example (1 lb, Zone 4)';
cellPrice.textContent = '$6.25'; // Example rate
row = pricingTableBody.insertRow();
cellWeight = row.insertCell(0);
cellPrice = row.insertCell(1);
cellWeight.textContent = 'Example (3 lbs, Zone 7)';
cellPrice.textContent = '$7.50'; // Example rate
}
}
function updateChartData() {
var mailpieceType = document.getElementById('mailpieceType').value;
var weightInput = document.getElementById('weightOunces');
var weight = parseFloat(weightInput.value) || 0;
// Update Cost vs. Weight Chart (Standard Letter)
var ctx1 = document.getElementById('costWeightChart').getContext('2d');
var weights = [];
var costs = [];
var pricingData = getPricingData().letter;
for (var w = 0.1; w 1) {
var additionalOunces = Math.ceil(w) – 1;
currentCost += additionalOunceRate * additionalOunces;
}
// Cap at a reasonable max or use tier data if available for this chart
if (w > 3.5) currentCost = pricingData.firstOunce + (Math.ceil(3.5) – 1) * additionalOunceRate; // Cap at max letter weight cost
if (currentCost > 4.00) currentCost = 4.00; // Cap for visualization purposes
costs.push(currentCost);
}
if (window.costWeightChartInstance) {
window.costWeightChartInstance.destroy();
}
window.costWeightChartInstance = new Chart(ctx1, {
type: 'line',
data: {
labels: weights.map(function(w) { return w.toFixed(1) + ' oz'; }),
datasets: [{
label: 'Estimated Cost ($)',
data: costs,
borderColor: 'rgb(0, 74, 153)',
backgroundColor: 'rgba(0, 74, 153, 0.2)',
fill: true,
tension: 0.1
}]
},
options: {
responsive: true,
maintainAspectRatio: false,
scales: {
x: {
title: { display: true, text: 'Weight (ounces)' }
},
y: {
title: { display: true, text: 'Cost ($)' },
beginAtZero: true
}
},
plugins: {
tooltip: {
callbacks: {
label: function(context) {
var label = context.dataset.label || ";
if (label) {
label += ': ';
}
if (context.parsed.y !== null) {
label += '$' + context.parsed.y.toFixed(2);
}
return label;
}
}
}
}
}
});
// Update Zone Cost Chart (1 lb Package)
var ctx2 = document.getElementById('zoneCostChart').getContext('2d');
var zones = [];
var packageCosts = [];
var packageWeightLbs = 1; // For a 1 lb package
var pricingDataPkg = getPricingData().package;
for (var z = 1; z maxWeight) {
postageType = 'Exceeds Letter Weight Limit';
totalCost = Infinity; // Indicate it's too heavy
calculatedWeightCost = firstOunceRate;
calculatedAdditionalOunceCost = additionalOunceRate * (maxWeight – 1);
} else {
calculatedWeightCost = firstOunceRate;
var additionalOunces = 0;
if (weightOz > 1) {
additionalOunces = Math.ceil(weightOz) – 1;
calculatedAdditionalOunceCost = additionalOunceRate * additionalOunces;
}
totalCost = calculatedWeightCost + calculatedAdditionalOunceCost;
}
dimensionalWeightSpan.parentElement.style.display = 'none'; // Hide dimensional weight for letters
} else if (mailpieceType === 'largeEnvelope') {
postageType = 'First-Class Mail Flat';
var firstOunceRate = pricingData.largeEnvelope.firstOunce;
var additionalOunceRate = pricingData.largeEnvelope.additionalOunce;
var maxWeight = pricingData.largeEnvelope.maxWeight;
if (weightOz > maxWeight) {
postageType = 'Exceeds Flat Weight Limit';
totalCost = Infinity;
calculatedWeightCost = firstOunceRate;
calculatedAdditionalOunceCost = additionalOunceRate * (maxWeight – 1);
} else {
calculatedWeightCost = firstOunceRate;
var additionalOunces = 0;
if (weightOz > 1) {
additionalOunces = Math.ceil(weightOz) – 1;
calculatedAdditionalOunceCost = additionalOunceRate * additionalOunces;
}
totalCost = calculatedWeightCost + calculatedAdditionalOunceCost;
}
dimensionalWeightSpan.parentElement.style.display = 'none'; // Hide dimensional weight for flats
} else { // Package
postageType = 'USPS Ground Advantage (Example)'; // Defaulting to a common service
var weightLbs = weightOz / 16;
calculatedDimWeight = (length * width * height) / packageDimWeightFactor;
var pricingWeight = Math.max(weightLbs, calculatedDimWeight); // Use the greater of actual or dimensional weight
// Convert pricingWeight back to ounces for display clarity if needed, or keep lbs
var displayPricingWeightOz = pricingWeight * 16;
// Use the package pricing logic
totalCost = pricingData.package.getRate(pricingWeight, destinationZone);
dimensionalWeightSpan.parentElement.style.display = "; // Show dimensional weight for packages
dimensionalWeightSpan.textContent = displayPricingWeightOz.toFixed(2);
calculatedWeightCost = 0; // Not directly applicable in this simplified package model
calculatedAdditionalOunceCost = 0; // Not directly applicable in this simplified package model
}
primaryResult.textContent = '$' + totalCost.toFixed(2);
weightCostSpan.textContent = '$' + calculatedWeightCost.toFixed(2);
additionalOunceCostSpan.textContent = '$' + calculatedAdditionalOunceCost.toFixed(2);
postageTypeSpan.textContent = postageType;
// Update charts after calculation
updateChartData();
// Update table caption if type changes significantly
updatePricingTable();
}
function resetCalculator() {
document.getElementById('mailpieceType').value = 'letter';
document.getElementById('weightOunces').value = '1';
document.getElementById('dimensionsLength').value = ";
document.getElementById('dimensionsWidth').value = ";
document.getElementById('dimensionsHeight').value = ";
document.getElementById('destinationZone').value = '1';
// Clear errors
document.getElementById('weightOuncesError').textContent = ";
document.getElementById('dimensionsLengthError').textContent = ";
document.getElementById('dimensionsWidthError').textContent = ";
document.getElementById('dimensionsHeightError').textContent = ";
calculatePostage(); // Recalculate with default values
}
function updateCalculator() {
// This function is called when inputs change but before the explicit calculate button press
// It can be used to show live preview or update dependent fields
var mailpieceType = document.getElementById('mailpieceType').value;
// Show/hide dimension inputs based on type
var dimInputs = [
document.getElementById('dimensionsLength').parentElement,
document.getElementById('dimensionsWidth').parentElement,
document.getElementById('dimensionsHeight').parentElement,
document.getElementById('destinationZone').parentElement
];
if (mailpieceType === 'letter') {
for (var i = 0; i < dimInputs.length; i++) {
dimInputs[i].style.display = 'none';
}
document.getElementById('weightOunces').placeholder = "e.g., 1";
document.getElementById('weightOunces').setAttribute('maxlength', '4'); // Limit input length for ounces
document.getElementById('weightOunces').setAttribute('max', '3.5'); // Set max attribute for letter weight
} else {
for (var i = 0; i < dimInputs.length; i++) {
dimInputs[i].style.display = '';
}
document.getElementById('weightOunces').placeholder = "e.g., 16"; // For lbs, or keep oz and adjust logic
document.getElementById('weightOunces').setAttribute('maxlength', '5');
document.getElementById('weightOunces').setAttribute('max', '70*16'); // Max weight for packages is 70 lbs
// Update helper text for dimensions based on type
document.querySelector('#dimensionsLength ~ .helper-text').textContent = mailpieceType === 'largeEnvelope' ? 'For flats (e.g., 9.5 x 12.5 inches).' : 'For packages (e.g., 8 inches). Max 108 inches combined L+Girth.';
document.querySelector('#dimensionsWidth ~ .helper-text').textContent = mailpieceType === 'largeEnvelope' ? 'For flats (e.g., 12.5 inches).' : 'For packages (e.g., 6 inches).';
document.querySelector('#dimensionsHeight ~ .helper-text').textContent = mailpieceType === 'largeEnvelope' ? 'For flats (e.g., 0.75 inches max).' : 'For packages (e.g., 3 inches). Max 12 inches.';
document.querySelector('#destinationZone ~ .helper-text').textContent = 'Enter the USPS destination zone (1-8). Local is Zone 1.';
// Adjust validation max if needed
if (mailpieceType === 'largeEnvelope') {
document.getElementById('weightOunces').setAttribute('max', '13');
document.getElementById('dimensionsLength').setAttribute('max', '15'); // Typical flat dimension max
document.getElementById('dimensionsWidth').setAttribute('max', '12');
document.getElementById('dimensionsHeight').setAttribute('max', '0.75');
} else { // Package
document.getElementById('weightOunces').setAttribute('max', '1120'); // 70 lbs * 16 oz/lb
document.getElementById('dimensionsLength').setAttribute('max', '108');
document.getElementById('dimensionsWidth').setAttribute('max', '54'); // Example limits
document.getElementById('dimensionsHeight').setAttribute('max', '12');
}
}
// Recalculate immediately if calculatePostage is called on change
calculatePostage();
// Update Pricing Table view
updatePricingTable();
}
function copyResults() {
var primaryResult = document.getElementById('primaryResult').textContent;
var weightCost = document.getElementById('weightCost').querySelector('span').textContent;
var additionalOunceCost = document.getElementById('additionalOunceCost').querySelector('span').textContent;
var postageType = document.getElementById('postageType').querySelector('span').textContent;
var dimWeight = document.getElementById('dimensionalWeight').querySelector('span').textContent;
var mailpieceType = document.getElementById('mailpieceType').value;
var weight = document.getElementById('weightOunces').value;
var length = document.getElementById('dimensionsLength').value;
var width = document.getElementById('dimensionsWidth').value;
var height = document.getElementById('dimensionsHeight').value;
var zone = document.getElementById('destinationZone').value;
var assumptions = `Key Assumptions:\n`;
assumptions += `- Mailpiece Type: ${mailpieceType}\n`;
assumptions += `- Weight: ${weight} oz\n`;
if (mailpieceType !== 'letter') {
assumptions += `- Length: ${length} in\n`;
assumptions += `- Width: ${width} in\n`;
assumptions += `- Height: ${height} in\n`;
assumptions += `- Destination Zone: ${zone}\n`;
}
var resultText = `— USPS Postage Calculation —
\nPrimary Estimated Cost: ${primaryResult}
\nIntermediate Costs:
– First Ounce/Base Cost: ${weightCost}
– Additional Ounce Cost: ${additionalOunceCost}
\nDetails:
– Postage Type: ${postageType}
`;
if (mailpieceType !== 'letter') {
resultText += `- Dimensional Weight (estimated): ${dimWeight} oz\n`;
}
resultText += `\n${assumptions}`;
// Use the modern Clipboard API if available, otherwise fallback
if (navigator.clipboard && navigator.clipboard.writeText) {
navigator.clipboard.writeText(resultText).then(function() {
showCopyFeedback();
}).catch(function(err) {
console.error('Failed to copy text: ', err);
fallbackCopyTextToClipboard(resultText); // Fallback
});
} else {
fallbackCopyTextToClipboard(resultText);
}
}
function fallbackCopyTextToClipboard(text) {
var textArea = document.createElement("textarea");
textArea.value = text;
// Avoid scrolling to bottom
textArea.style.top = "0";
textArea.style.left = "0";
textArea.style.position = "fixed";
document.body.appendChild(textArea);
textArea.focus();
textArea.select();
try {
var successful = document.execCommand('copy');
if (successful) {
showCopyFeedback();
} else {
console.error('Fallback: copy command failed');
alert('Failed to copy text. Please copy manually.');
}
} catch (err) {
console.error('Fallback: Oops, unable to copy', err);
alert('Failed to copy text. Please copy manually.');
}
document.body.removeChild(textArea);
}
function showCopyFeedback() {
var feedback = document.getElementById('copyFeedback');
feedback.classList.add('show');
setTimeout(function() {
feedback.classList.remove('show');
}, 3000); // Hide after 3 seconds
}
// Initialize the calculator on page load
window.onload = function() {
// Ensure canvas elements exist before trying to chart
var canvas1 = document.getElementById('costWeightChart');
var canvas2 = document.getElementById('zoneCostChart');
if (canvas1 && canvas1.getContext && canvas2 && canvas2.getContext) {
updateChartData();
} else {
console.error("Canvas element not found or context not supported.");
}
resetCalculator(); // Load with default values
updatePricingTable(); // Load pricing table
};
// Add Chart.js library dynamically or ensure it's included if running standalone
// For this single-file HTML, we assume Chart.js is available globally
// If not, you'd need to add: in the
// Or include the library content directly if required by constraints.
// For this example, assuming Chart.js is loaded externally.