Estimate your postage costs for 2025 based on projected rate increases for First-Class Mail, Postcards, and Large Envelopes.
Standard Letter (1 oz – 3.5 oz)
Large Envelope / Flat (1 oz – 13 oz)
Postcard
International Letter (1 oz)
Postage is calculated per ounce or fraction thereof.
Retail Stamp (Post Office)
Metered Mail / Online Postage
$0.00
Understanding Postal Rates in 2025
The United States Postal Service (USPS) typically adjusts postage rates twice a year, in January and July. As operating costs and inflation fluctuate, the "Forever Stamp" price and associated fees for additional ounces and international mail are expected to rise. This calculator uses projected 2025 rates based on recent Market Dominant price adjustment trends.
Projected 2025 Rate Table (Estimates)
The following table outlines the estimated costs used in this calculator. These figures anticipate a standard inflationary increase from late 2024 rates.
Mail Service
Base Price (1 oz)
Additional Ounce
First-Class Letter (Stamped)
$0.78 (Est.)
+$0.30
First-Class Letter (Metered)
$0.73 (Est.)
+$0.30
Large Envelope (Flats)
$1.59 (Est.)
+$0.30
Domestic Postcard
$0.61 (Est.)
N/A
International Letter
$1.75 (Est.)
N/A
How Postage is Calculated
Postage for First-Class Mail is determined by the shape of the mailpiece and its weight. The logic works as follows:
Base Rate: Covers the first ounce of weight.
Additional Ounces: If your letter weighs 1.1 ounces, the USPS charges you for 2 ounces. Always round up to the next whole ounce for calculation purposes.
Shape Matters: A square envelope or a rigid envelope that cannot pass through automated processing machines may be subject to a "non-machinable surcharge" (typically $0.46 extra), though this calculator focuses on standard flexible envelopes.
Weight Limits
It is crucial to select the correct mail class based on weight:
Standard Letters: Maximum weight is 3.5 oz. Above this, it must be mailed as a Large Envelope (Flat).
Large Envelopes: Maximum weight is 13 oz. Above this, it becomes First-Class Package Service (Ground Advantage).
Saving with Metered Mail
If you use an office postage meter or print postage online (via services like Stamps.com or Pitney Bowes), you typically pay a lower rate for the first ounce compared to buying physical stamps at the Post Office. In 2025, this discount is expected to remain approximately 5 cents per letter.
function toggleMeterOption() {
var mailClass = document.getElementById("mailClass").value;
var meterGroup = document.getElementById("meterGroup");
var weightGroup = document.getElementById("weightGroup");
// Metered discount generally applies to standard letters
if (mailClass === "letter") {
meterGroup.style.display = "block";
} else {
meterGroup.style.display = "none";
}
// Postcards have fixed weight constraints usually, but we keep weight hidden for postcard implies single card
if (mailClass === "postcard" || mailClass === "intl") {
// For simple calculator, assume 1 oz limit/standard for intl letter basic rate
// weightGroup.style.display = "none";
// Actually, keep weight for Int'l as it scales, but let's simplify to 1oz base for this specific tool request
// or keep it simple. Let's keep weight visible but note it's mostly 1oz base for simple intl.
} else {
weightGroup.style.display = "block";
}
}
function calculatePostage() {
// Clear errors
document.getElementById("errorBox").style.display = "none";
document.getElementById("result").style.display = "none";
// Inputs
var mailClass = document.getElementById("mailClass").value;
var weightVal = document.getElementById("weightInput").value;
var method = document.getElementById("paymentMethod").value;
// Validation
if (mailClass !== "postcard" && (!weightVal || weightVal 3.5) {
showError("Standard letters cannot weigh more than 3.5 oz. Please select 'Large Envelope / Flat'.");
return;
}
// Calculate Ounces (Rounded up)
var chargeableOz = Math.ceil(weight);
var basePrice = (method === "metered") ? rateMeteredBase : rateStampBase;
if (chargeableOz === 1) {
cost = basePrice;
breakdownText = "Base rate (1 oz): $" + basePrice.toFixed(2);
} else {
var additionalOz = chargeableOz – 1;
cost = basePrice + (additionalOz * rateAddOz);
breakdownText = "Base (1 oz): $" + basePrice.toFixed(2) + " + " + additionalOz + " add'l oz @ $" + rateAddOz.toFixed(2);
}
}
else if (mailClass === "flat") {
if (weight > 13) {
showError("Large Envelopes cannot weigh more than 13 oz. This is considered a package (Ground Advantage).");
return;
}
var chargeableOz = Math.ceil(weight);
if (chargeableOz === 1) {
cost = rateFlatBase;
breakdownText = "Base rate (1 oz): $" + rateFlatBase.toFixed(2);
} else {
var additionalOz = chargeableOz – 1;
cost = rateFlatBase + (additionalOz * rateAddOz);
breakdownText = "Base (1 oz): $" + rateFlatBase.toFixed(2) + " + " + additionalOz + " add'l oz @ $" + rateAddOz.toFixed(2);
}
}
else if (mailClass === "intl") {
// Simplified International (Global Forever covers 1 oz)
// Note: Heavy international letters vary by group. We assume standard 1oz Global Forever usage.
if (weight > 1 && weight <= 15.99) {
breakdownText = "Note: Weights over 1 oz for international mail vary by country group. Showing Base Rate only.";
}
cost = rateIntl;
breakdownText = (breakdownText ? breakdownText + " " : "") + "Global Forever Stamp (1 oz).";
}
// Display Result
document.getElementById("totalCost").innerHTML = "$" + cost.toFixed(2);
document.getElementById("breakdown").innerHTML = breakdownText;
document.getElementById("result").style.display = "block";
}
function showError(msg) {
var errBox = document.getElementById("errorBox");
errBox.innerHTML = msg;
errBox.style.display = "block";
}