Easily calculate your estimated postage costs by simply entering the weight of your package. Our postage price calculator by weight provides real-time estimates to help you budget for shipping.
Shipping Cost Estimator
Enter the weight of your package. Use decimal for fractions (e.g., 0.25 for 1/4 lb).
Pounds (lb)
Kilograms (kg)
Ounces (oz)
Grams (g)
Select the unit of measurement for your package weight.
Standard (e.g., USPS Ground Advantage)
Priority (e.g., USPS Priority Mail)
Express (e.g., USPS Priority Mail Express)
Choose the shipping service that best fits your needs for speed and cost.
Zone 1 (Local)
Zone 2
Zone 3
Zone 4
Zone 5
Zone 6
Zone 7
Zone 8 (Far)
Select the shipping zone based on the distance to the destination.
Estimated Postage Cost
$–.–
Base Rate$–.–
Weight Factor–.–
Zone Surcharge$–.–
Formula Used:
The estimated postage price is calculated based on a base rate for the selected service type, adjusted by a weight factor derived from the package weight and unit, and potentially increased by a zone surcharge dependent on the destination. Specific carrier pricing tables determine these values. This calculator uses simplified, representative pricing models.
Cost by Weight Comparison
Visualizing estimated costs for different service types across a range of weights for Zone 4.
Sample Postage Rates (Zone 4, Standard Service)
Weight (lb)
Ounces (oz)
Estimated Price ($)
What is a Postage Price Calculator by Weight?
A Postage Price Calculator by Weight is a specialized online tool designed to estimate the cost of sending mail or packages based primarily on how much they weigh. It simplifies the often complex pricing structures of postal services (like USPS, FedEx, UPS, etc.) by allowing users to input their package's weight, select relevant parameters like service type and destination, and receive an immediate cost estimate. This tool is invaluable for individuals and businesses looking to budget for shipping expenses, compare carrier prices, or ensure they are using the most cost-effective shipping method for their needs. Understanding the postage price calculator by weight helps demystify shipping costs.
This calculator is particularly useful for:
E-commerce sellers: To accurately charge customers for shipping and manage inventory costs.
Small businesses: For planning operational expenses related to sending documents or products.
Individuals: When sending gifts, documents, or personal items to friends and family.
Anyone needing to ship an item and wanting a quick, reliable estimate without visiting a post office or manually sifting through complex rate charts.
Common misconceptions include believing that weight is the *only* factor determining postage. While weight is critical, other factors such as package dimensions (dimensional weight), destination zone, service speed (e.g., first-class, priority, express), insurance, and special handling can significantly influence the final price. Our postage price calculator by weight aims to incorporate key variables for a more comprehensive estimate.
Postage Price Calculator by Weight Formula and Mathematical Explanation
The exact formula for calculating postage prices is proprietary to each shipping carrier and can be quite intricate. However, a generalized model used by many online postage price calculator by weight tools can be represented as:
The actual physical mass of the item(s) being shipped.
lb, kg, oz, g
0.1 oz to 150 lbs (varies by carrier and service)
Weight Unit
The unit of measurement for the package weight.
N/A
lb, kg, oz, g
Service Type
The speed and class of mail/package delivery chosen (e.g., Standard, Priority, Express).
N/A
Determines base rates and delivery timelines.
Destination Zone
Geographical area based on distance from the origin zip code.
Zone Number (e.g., Zone 1-8 for USPS)
Zone 1 (local) to Zone 8 (coast-to-coast).
Base Rate
The starting price for a specific service type, often for the smallest weight increment.
Currency ($)
Varies significantly by carrier and service.
Weight Multiplier
A factor applied to the base rate or a per-unit-weight cost, often tiered.
Unitless or Currency per Unit Weight
Calculated based on weight and carrier's pricing table. For simplicity, our calculator uses a simplified factor.
Zone Surcharge
An additional cost applied based on the distance (zone) to the destination.
Currency ($)
Increases with higher zone numbers.
Additional Fees
Costs for extras like insurance, signature confirmation, oversized packages, etc.
Currency ($)
Optional services. Not included in this basic calculator.
Mathematical Derivation Simplified: Our calculator approximates the postage price by combining a base rate tied to the service type, a multiplier that scales with weight, and a zone-dependent adjustment. For example, a common simplified approach might look like this:
Effective Price = (Base Rate for Service Type) + (Weight in lbs * $ per lb) + (Zone Factor * Zone Number)
The calculator internally converts all weights to a common unit (e.g., pounds) for consistent calculation before applying these simplified rates. The chart and table demonstrate how this simplified model affects price across different weights and services.
Practical Examples (Real-World Use Cases)
Let's illustrate with two common scenarios using our postage price calculator by weight:
Example 1: Sending a Book to a Neighbor
Scenario: Sarah wants to mail a used textbook to a friend who lives in a different state, but within the same general region. She needs it to arrive relatively quickly but doesn't need it overnight.
Package Weight: 3.2 lbs
Weight Unit: Pounds (lb)
Service Type: Priority (e.g., USPS Priority Mail)
Destination Zone: Zone 4
Calculator Input:
Package Weight: 3.2
Weight Unit: lb
Service Type: Priority
Destination Zone: Zone 4
Calculator Output (Hypothetical):
Estimated Postage Cost: $12.75
Base Rate: $8.50 (for Priority Mail starting weight)
Weight Factor: $1.06 (approx. $1.06 per lb adjustment)
Zone Surcharge: $3.19 (approx. $0.79 per lb for Zone 4)
Financial Interpretation: For a 3.2 lb book going to Zone 4 via Priority Mail, the estimated cost is $12.75. This breaks down into the initial service fee, an added cost proportional to the weight, and a further increase due to the shipping distance. Sarah can use this estimate to decide if this method is cost-effective for her.
Example 2: Shipping Small Items Internationally (Simulated Domestic)
Scenario: A small online business needs to ship a package containing handcrafted jewelry to a customer on the opposite coast. They typically use a standard, more economical service.
Package Weight: 12 oz
Weight Unit: Ounces (oz)
Service Type: Standard (e.g., USPS Ground Advantage)
Destination Zone: Zone 7
Calculator Input:
Package Weight: 12
Weight Unit: oz
Service Type: Standard
Destination Zone: Zone 7
Calculator Output (Hypothetical):
Estimated Postage Cost: $7.80
Base Rate: $5.20 (for Standard Service starting weight)
Weight Factor: $0.22 (approx. $0.022 per oz adjustment)
Zone Surcharge: $2.38 (approx. $0.20 per oz for Zone 7)
Financial Interpretation: Shipping 12 oz via Standard Service to a distant zone (Zone 7) costs approximately $7.80. The higher zone surcharge significantly impacts the price compared to a local shipment. The business can use this to set shipping prices for their customers, considering that heavier items or items going to further zones will cost more. This is a key insight for any small business relying on a robust postage price calculator by weight.
How to Use This Postage Price Calculator by Weight
Using our postage price calculator by weight is straightforward. Follow these simple steps:
Enter Package Weight: Input the precise weight of your package into the "Package Weight" field. Use decimals if necessary (e.g., 2.5 for two and a half pounds).
Select Weight Unit: Choose the correct unit of measurement (Pounds, Kilograms, Ounces, or Grams) from the "Weight Unit" dropdown menu that corresponds to how you measured your package.
Choose Service Type: Select the desired shipping speed and service from the "Service Type" dropdown. Options typically range from economical standard services to faster, premium options.
Determine Destination Zone: Select the appropriate "Destination Zone" based on the distance between your shipment's origin and destination. Most carriers provide zone maps or calculators on their websites if you're unsure.
Click Calculate: Press the "Calculate Postage" button.
Reading the Results:
Estimated Postage Cost: This is the primary output – your projected cost for shipping.
Base Rate: The foundational cost associated with your chosen service type.
Weight Factor: How much the weight is contributing to the overall cost.
Zone Surcharge: Any additional cost added due to the shipping distance.
Decision-Making Guidance: Use the calculated price to compare with other carriers or services. If the cost seems high, consider if a slower service type or a different packaging strategy (to reduce weight or size) might be more economical. This postage price calculator by weight provides the data you need to make informed shipping decisions.
Key Factors That Affect Postage Price Results
While weight is a primary driver, several other factors interact with weight to determine the final postage cost. Understanding these nuances is crucial for accurate budgeting and can impact the effectiveness of any postage price calculator by weight:
Actual Weight vs. Dimensional (Dim) Weight: Carriers often charge based on whichever is greater: the package's actual weight or its dimensional weight. Dim weight is calculated from the package's volume (Length x Width x Height) divided by a dimensional factor. Bulky but light items can incur higher costs based on dim weight.
Service Speed and Type: As seen in the calculator, selecting Priority or Express mail costs significantly more than Standard or First-Class mail due to faster delivery guarantees and higher handling priority.
Destination Distance (Zones): Shipping costs increase dramatically with distance. Zone 1 (local) is cheapest, while Zone 8 (coast-to-coast) is the most expensive. Our calculator uses these zones to adjust pricing.
Package Dimensions: Beyond dim weight, oversized packages might incur additional surcharges regardless of actual weight, due to special handling requirements.
Insurance and Declared Value: Adding shipping insurance to cover the value of the contents increases the total cost. The higher the declared value, the higher the insurance premium.
Additional Services: Options like signature confirmation, adult signature required, return receipt, special handling (fragile, perishable), and remote area delivery fees all add to the base postage price.
Fuel Surcharges: Carriers often adjust prices based on fluctuating fuel costs. These are typically variable percentage add-ons to the base rates.
Carrier-Specific Pricing Tables: Each carrier (USPS, FedEx, UPS, DHL) has its own unique, complex pricing tables, discounts, and surcharges. A good postage price calculator by weight uses representative data but may not perfectly match every carrier's live rates.
Frequently Asked Questions (FAQ)
Q1: How accurate is this postage price calculator by weight?
A: This calculator provides an *estimate* based on common pricing structures. Actual costs can vary slightly depending on the specific carrier, your exact origin/destination zip codes, current fuel surcharges, and any special handling or packaging requirements. It's best used for budgeting and comparison.
Q2: Does the calculator account for package dimensions?
A: This calculator primarily uses *actual weight*. While it considers 'weight' broadly, it doesn't calculate dimensional weight. For bulky, lightweight items, dimensional weight could be the determining factor, and you'd need to consult the specific carrier's calculator for precise pricing.
Q3: What is the difference between Standard, Priority, and Express mail?
A: Standard mail is the most economical but slowest option. Priority mail offers faster delivery (typically 1-3 business days) at a moderate price increase. Express mail is the fastest, often with overnight or 1-2 day guarantees, and comes at the highest cost.
Q4: How do I find my destination zone?
A: Most major carriers (like USPS) have zone charts available on their websites. You typically input your origin and destination zip codes into their tool to determine the corresponding zone number.
Q5: Can I use this calculator for international shipping?
A: This specific calculator is designed for domestic (within country) shipping estimates, using common domestic zone structures. International rates are significantly more complex and vary widely by country and customs regulations.
Q6: What if my package weight is exactly on the border between two weight classes?
A: Postal services usually round up to the next weight increment. For example, if the rate changes at 1 lb, a 1.1 lb package would be charged the rate for the next tier (e.g., 2 lb). Always check the carrier's specific rules.
Q7: Does the price include insurance?
A: This calculator typically provides the base postage cost and does not automatically include the cost of shipping insurance or other add-on services unless specified. You usually need to opt-in and pay extra for these.
Q8: Why is the "Weight Factor" and "Zone Surcharge" sometimes zero or very low?
A: In simplified models, the "Base Rate" might already incorporate a certain weight and zone. Or, for very light packages or local zones (Zone 1), the additional calculated factor might be negligible compared to the base rate. The calculator aims to reflect general trends.
Q9: How often do postage prices change?
A: Postal services typically adjust their rates annually, though sometimes mid-year adjustments occur, especially concerning fuel surcharges or economic factors. It's good practice to periodically check for updated rates.
var baseRates = {
standard: { lb: 5.00, kg: 11.00, oz: 3.50, g: 0.12 },
priority: { lb: 8.50, kg: 18.70, oz: 6.00, g: 0.21 },
express: { lb: 25.00, kg: 55.00, oz: 17.50, g: 0.62 }
};
var weightFactors = { // Additional cost per lb for heavier items or just scaling
standard: { lb: 0.50, kg: 1.10, oz: 0.03, g: 0.005 },
priority: { lb: 1.00, kg: 2.20, oz: 0.07, g: 0.012 },
express: { lb: 3.00, kg: 6.60, oz: 0.21, g: 0.035 }
};
var zoneSurcharges = { // Per lb surcharge based on zone
zone1: { lb: 0.10, kg: 0.22, oz: 0.01, g: 0.001 },
zone2: { lb: 0.25, kg: 0.55, oz: 0.02, g: 0.002 },
zone3: { lb: 0.40, kg: 0.88, oz: 0.03, g: 0.003 },
zone4: { lb: 0.75, kg: 1.65, oz: 0.05, g: 0.007 },
zone5: { lb: 1.10, kg: 2.42, oz: 0.08, g: 0.011 },
zone6: { lb: 1.45, kg: 3.19, oz: 0.10, g: 0.014 },
zone7: { lb: 1.80, kg: 3.96, oz: 0.13, g: 0.018 },
zone8: { lb: 2.15, kg: 4.73, oz: 0.15, g: 0.021 }
};
var chartData = {
labels: [],
standard: [],
priority: [],
express: []
};
var myChart = null;
function initializeChart() {
var ctx = document.getElementById('postageCostChart').getContext('2d');
chartData.labels = [];
for (var i = 0; i <= 10; i += 0.5) { // Sample weights from 0 to 10 lbs
chartData.labels.push(i + ' lb');
}
var selectedZoneForChart = "zone4"; // Fixed zone for chart comparison
for (var i = 0; i < chartData.labels.length; i++) {
var weightLb = parseFloat(chartData.labels[i].replace(' lb', ''));
if (isNaN(weightLb)) continue;
var weightOz = weightLb * 16;
var weightG = weightLb * 453.592;
var weightKg = weightLb * 0.453592;
chartData.standard.push(calculateSingleRate('standard', weightLb, 'lb', selectedZoneForChart));
chartData.priority.push(calculateSingleRate('priority', weightLb, 'lb', selectedZoneForChart));
chartData.express.push(calculateSingleRate('express', weightLb, 'lb', selectedZoneForChart));
}
myChart = new Chart(ctx, {
type: 'line',
data: {
labels: chartData.labels,
datasets: [{
label: 'Standard',
data: chartData.standard,
borderColor: 'rgba(0, 74, 153, 1)',
backgroundColor: 'rgba(0, 74, 153, 0.2)',
fill: false,
tension: 0.1
}, {
label: 'Priority',
data: chartData.priority,
borderColor: 'rgba(40, 167, 69, 1)',
backgroundColor: 'rgba(40, 167, 69, 0.2)',
fill: false,
tension: 0.1
}, {
label: 'Express',
data: chartData.express,
borderColor: 'rgba(255, 193, 7, 1)',
backgroundColor: 'rgba(255, 193, 7, 0.2)',
fill: false,
tension: 0.1
}]
},
options: {
responsive: true,
maintainAspectRatio: true,
scales: {
y: {
beginAtZero: true,
title: {
display: true,
text: 'Estimated Cost ($)'
}
},
x: {
title: {
display: true,
text: 'Package Weight (lbs)'
}
}
},
plugins: {
title: {
display: true,
text: 'Estimated Postage Cost vs. Weight by Service Type (Zone 4)'
}
}
}
});
}
function populatePriceTable() {
var tableBody = document.getElementById('priceTableBody');
tableBody.innerHTML = ''; // Clear previous rows
var weights = [0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; // Sample weights in lbs
var selectedService = 'standard'; // Fixed service for table
var selectedZone = 'zone4'; // Fixed zone for table
weights.forEach(function(weightLb) {
var weightOz = weightLb * 16;
var price = calculateSingleRate(selectedService, weightLb, 'lb', selectedZone);
var row = tableBody.insertRow();
row.insertCell(0).textContent = weightLb.toFixed(1);
row.insertCell(1).textContent = weightOz.toFixed(1);
row.insertCell(2).textContent = '$' + price.toFixed(2);
});
}
function calculateSingleRate(serviceType, weightValue, weightUnit, zone) {
var baseRate = baseRates[serviceType][weightUnit] || 0;
var weightFactorRate = weightFactors[serviceType][weightUnit] || 0;
var zoneSurchargeRate = zoneSurcharges[zone][weightUnit] || 0;
// Convert all to a common unit for calculation, e.g., pounds
var weightInPounds = weightValue;
if (weightUnit === 'kg') weightInPounds = weightValue * 0.453592;
else if (weightUnit === 'oz') weightInPounds = weightValue / 16;
else if (weightUnit === 'g') weightInPounds = weightValue / 453.592;
// Adjust rates to be per pound if they aren't already
var baseRatePerLb = baseRate;
var weightFactorPerLb = weightFactorRate;
var zoneSurchargePerLb = zoneSurchargeRate;
if (weightUnit !== 'lb') {
if (weightUnit === 'kg') {
baseRatePerLb = baseRate / 0.453592;
weightFactorPerLb = weightFactorRate / 0.453592;
zoneSurchargePerLb = zoneSurchargeRate / 0.453592;
} else if (weightUnit === 'oz') {
baseRatePerLb = baseRate * 16;
weightFactorPerLb = weightFactorRate * 16;
zoneSurchargePerLb = zoneSurchargeRate * 16;
} else if (weightUnit === 'g') {
baseRatePerLb = baseRate * 453.592;
weightFactorPerLb = weightFactorRate * 453.592;
zoneSurchargePerLb = zoneSurchargeRate * 453.592;
}
}
// Simplified calculation: Base rate + scaling factor based on weight + zone cost
// For simplicity, let's use a tiered approach or direct scaling.
// Here, we'll approximate: base + additional per lb + zone specific per lb cost
var calculatedBaseRate = baseRates[serviceType][weightUnit] || 0; // Use the rate for the selected unit
// A more realistic model might involve base rate for first X weight, then per unit after.
// Let's simplify to: Base + (weight * factor) + (weight * zone_factor)
// We will convert all inputs to lbs for internal calc consistency.
var weightInPoundsCalc = weightValue;
if (weightUnit === 'kg') weightInPoundsCalc = weightValue * 2.20462;
else if (weightUnit === 'oz') weightInPoundsCalc = weightValue / 16;
else if (weightUnit === 'g') weightInPoundsCalc = weightValue / 453.592;
var adjustedBaseRate = baseRates[serviceType]['lb'] || 0; // Use lb rates as base reference
var adjustedWeightFactor = weightFactors[serviceType]['lb'] || 0;
var adjustedZoneSurcharge = zoneSurcharges[zone]['lb'] || 0;
var finalPrice = adjustedBaseRate + (weightInPoundsCalc * adjustedWeightFactor) + (weightInPoundsCalc * adjustedZoneSurcharge);
// Ensure minimum price isn't less than the base rate for the actual unit
var minPriceForUnit = baseRates[serviceType][weightUnit] || 0;
if (finalPrice < minPriceForUnit) {
finalPrice = minPriceForUnit;
}
// Return the calculated price for the given unit for internal use
// For chart/table, we need to return a value ready for display. Let's assume lbs internally and convert back if needed.
// For simplicity, let's return value in the user's selected unit if the rates were defined for it
// Or convert everything to lbs, calculate, then show in dollars
return finalPrice;
}
function calculatePostage() {
var weightInput = document.getElementById('packageWeight');
var weightUnitSelect = document.getElementById('weightUnit');
var serviceTypeSelect = document.getElementById('serviceType');
var destinationZoneSelect = document.getElementById('destinationZone');
var weightValue = parseFloat(weightInput.value);
var weightUnit = weightUnitSelect.value;
var serviceType = serviceTypeSelect.value;
var zone = destinationZoneSelect.value;
var weightError = document.getElementById('weightError');
weightError.textContent = ''; // Clear previous errors
// — Validation —
if (isNaN(weightValue) || weightValue 150 && weightUnit === 'lb' || weightValue > 68 && weightUnit === 'kg') { // Approx max for USPS
weightError.textContent = 'Weight exceeds typical carrier limits (approx. 150 lbs / 68 kg).';
return;
}
// — Rate Conversion Helper —
function getRateValue(rateObject, unit, weightValue) {
var ratePerUnit = rateObject[unit];
if (ratePerUnit === undefined) {
// Fallback: Convert everything to pounds internally for calculation
var weightInPounds = weightValue;
if (unit === 'kg') weightInPounds = weightValue * 0.453592;
else if (unit === 'oz') weightInPounds = weightValue / 16;
else if (unit === 'g') weightInPounds = weightValue / 453.592;
var lbRate = rateObject['lb'] || 0;
var finalRate = lbRate + (weightInPounds * (rateObject['lb'] || 0)); // This needs more robust handling
// Let's rethink the rate structure – simpler is better for JS.
// Rates will be defined per BASE unit (e.g., per LB) and converted
return 0; // Placeholder, actual calc below
}
return ratePerUnit;
}
// — Calculation —
var calculatedBaseRate = baseRates[serviceType][weightUnit];
var calculatedWeightFactor = weightFactors[serviceType][weightUnit];
var calculatedZoneSurcharge = zoneSurcharges[zone][weightUnit];
// Convert inputs to a common unit (pounds) for consistent calculation
var weightInPounds = weightValue;
if (weightUnit === 'kg') weightInPounds = weightValue * 0.453592;
else if (weightUnit === 'oz') weightInPounds = weightValue / 16;
else if (weightUnit === 'g') weightInPounds = weightValue / 453.592;
// Get base rates and factors per pound
var baseRatePerLb = baseRates[serviceType]['lb'] || 0;
var weightFactorPerLb = weightFactors[serviceType]['lb'] || 0;
var zoneSurchargePerLb = zoneSurcharges[zone]['lb'] || 0;
// Handle cases where a unit might not be directly defined in rates, ensuring fallback to 'lb' based logic
if (calculatedBaseRate === undefined) calculatedBaseRate = baseRatePerLb;
if (calculatedWeightFactor === undefined) calculatedWeightFactor = weightFactorPerLb;
if (calculatedZoneSurcharge === undefined) calculatedZoneSurcharge = zoneSurchargePerLb;
// Simplified Calculation Model:
// Base Rate for service + (Weight in lbs * Factor per lb) + (Weight in lbs * Zone Surcharge per lb)
var finalPrice = baseRatePerLb + (weightInPounds * weightFactorPerLb) + (weightInPounds * zoneSurchargePerLb);
// Ensure the price is at least the minimum for the selected unit if defined
var minPriceForSelectedUnit = baseRates[serviceType][weightUnit];
if (minPriceForSelectedUnit !== undefined && finalPrice < minPriceForSelectedUnit) {
// However, our LB based calculation means we must ensure it's not less than the LB base rate.
if (finalPrice < baseRatePerLb) finalPrice = baseRatePerLb;
} else if (finalPrice < baseRatePerLb) { // Fallback if no specific unit min price
finalPrice = baseRatePerLb;
}
// Specific adjustment for very light items that might fall below a minimum threshold
// Example: A 0.1 oz item should probably cost more than the calculated fractional amount.
var minimumChargeableWeightOz = 1; // Example minimum chargeable weight in oz
var minimumChargeableWeight = minimumChargeableWeightOz / 16; // in lbs
if (weightInPounds < minimumChargeableWeight && finalPrice < (baseRates[serviceType]['lb'] || 0)) {
// If the calculated price is less than the base rate for the lightest service, use the base rate.
// Or perhaps a slightly higher minimum if defined for the service type.
finalPrice = Math.max(finalPrice, baseRates[serviceType]['lb'] || 0); // Use LB base rate as minimum
}
// — Intermediate Values Display —
var displayedBaseRate = baseRatePerLb; // Display using LB rate for consistency
var displayedWeightFactor = weightInPounds * weightFactorPerLb;
var displayedZoneSurcharge = weightInPounds * zoneSurchargePerLb;
document.getElementById('baseRate').textContent = '$' + displayedBaseRate.toFixed(2);
document.getElementById('weightFactor').textContent = '$' + displayedWeightFactor.toFixed(2);
document.getElementById('zoneSurcharge').textContent = '$' + displayedZoneSurcharge.toFixed(2);
// — Main Result Display —
document.getElementById('mainResult').textContent = '$' + finalPrice.toFixed(2);
document.getElementById('results-section').style.display = 'block';
// — Update Chart Data —
updateChart();
}
function updateChart() {
if (!myChart) return;
var selectedZoneForChart = "zone4"; // Fixed zone for chart comparison
var weightUnitSelect = document.getElementById('weightUnit'); // Get current unit
var currentWeightUnit = weightUnitSelect.value; // Store it
// Temporarily set unit to LB for chart calculations to ensure consistency
weightUnitSelect.value = 'lb';
chartData.standard = [];
chartData.priority = [];
chartData.express = [];
for (var i = 0; i < chartData.labels.length; i++) {
var weightLb = parseFloat(chartData.labels[i].replace(' lb', ''));
if (isNaN(weightLb)) continue;
chartData.standard.push(calculateSingleRate('standard', weightLb, 'lb', selectedZoneForChart));
chartData.priority.push(calculateSingleRate('priority', weightLb, 'lb', selectedZoneForChart));
chartData.express.push(calculateSingleRate('express', weightLb, 'lb', selectedZoneForChart));
}
myChart.data.datasets[0].data = chartData.standard;
myChart.data.datasets[1].data = chartData.priority;
myChart.data.datasets[2].data = chartData.express;
myChart.update();
// Restore the original weight unit
weightUnitSelect.value = currentWeightUnit;
}
function resetCalculator() {
document.getElementById('packageWeight').value = '1.0';
document.getElementById('weightUnit').value = 'lb';
document.getElementById('serviceType').value = 'standard';
document.getElementById('destinationZone').value = 'zone4';
document.getElementById('weightError').textContent = '';
document.getElementById('results-section').style.display = 'none';
document.getElementById('mainResult').textContent = '$–.–';
document.getElementById('baseRate').textContent = '$–.–';
document.getElementById('weightFactor').textContent = '–.–';
document.getElementById('zoneSurcharge').textContent = '$–.–';
// Reset chart if it exists (optional, as it's static until inputs change)
// updateChart(); // Could call this if chart depended on inputs too
}
function copyResults() {
var mainResult = document.getElementById('mainResult').textContent;
var baseRate = document.getElementById('baseRate').textContent;
var weightFactor = document.getElementById('weightFactor').textContent;
var zoneSurcharge = document.getElementById('zoneSurcharge').textContent;
var packageWeight = document.getElementById('packageWeight').value;
var weightUnit = document.getElementById('weightUnit').value;
var serviceType = document.getElementById('serviceType').options[document.getElementById('serviceType').selectedIndex].text;
var destinationZone = document.getElementById('destinationZone').options[document.getElementById('destinationZone').selectedIndex].text;
var copyText = "— Postage Cost Estimate —" + "\n" +
"Package Weight: " + packageWeight + " " + weightUnit + "\n" +
"Service Type: " + serviceType + "\n" +
"Destination Zone: " + destinationZone + "\n\n" +
"Estimated Postage Cost: " + mainResult + "\n" +
"Base Rate: " + baseRate + "\n" +
"Weight Factor Adjustment: " + weightFactor + "\n" +
"Zone Surcharge: " + zoneSurcharge + "\n\n" +
"Note: This is an estimate. Actual prices may vary by carrier.";
navigator.clipboard.writeText(copyText).then(function() {
alert('Results copied to clipboard!');
}, function(err) {
console.error('Async: Could not copy text: ', err);
alert('Failed to copy results.');
});
}
// Initialize on page load
document.addEventListener('DOMContentLoaded', function() {
initializeChart();
populatePriceTable();
// Optional: Trigger calculation on initial load with defaults
calculatePostage();
});