.first-class-mail-calculator-container {
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
max-width: 700px;
margin: 20px auto;
padding: 25px;
border: 1px solid #e0e0e0;
border-radius: 10px;
background-color: #f9f9f9;
box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}
.first-class-mail-calculator-container h2 {
color: #2c3e50;
text-align: center;
margin-bottom: 25px;
font-size: 1.8em;
}
.first-class-mail-calculator-container p {
color: #34495e;
line-height: 1.6;
margin-bottom: 15px;
}
.first-class-mail-calculator-container .input-group {
margin-bottom: 18px;
display: flex;
flex-direction: column;
}
.first-class-mail-calculator-container label {
display: block;
margin-bottom: 8px;
font-weight: bold;
color: #34495e;
font-size: 0.95em;
}
.first-class-mail-calculator-container input[type="number"],
.first-class-mail-calculator-container select {
width: calc(100% – 20px);
padding: 12px;
border: 1px solid #ccc;
border-radius: 6px;
font-size: 1em;
box-sizing: border-box;
transition: border-color 0.3s ease;
}
.first-class-mail-calculator-container input[type="number"]:focus,
.first-class-mail-calculator-container select:focus {
border-color: #007bff;
outline: none;
box-shadow: 0 0 5px rgba(0, 123, 255, 0.3);
}
.first-class-mail-calculator-container .checkbox-group {
display: flex;
align-items: center;
margin-top: 10px;
margin-bottom: 20px;
}
.first-class-mail-calculator-container .checkbox-group input[type="checkbox"] {
margin-right: 10px;
width: 18px;
height: 18px;
cursor: pointer;
}
.first-class-mail-calculator-container .checkbox-group label {
margin-bottom: 0;
font-weight: normal;
cursor: pointer;
}
.first-class-mail-calculator-container button {
background-color: #28a745;
color: white;
padding: 14px 25px;
border: none;
border-radius: 6px;
cursor: pointer;
font-size: 1.1em;
font-weight: bold;
width: 100%;
transition: background-color 0.3s ease, transform 0.2s ease;
margin-top: 15px;
}
.first-class-mail-calculator-container button:hover {
background-color: #218838;
transform: translateY(-2px);
}
.first-class-mail-calculator-container #calculationResult {
margin-top: 30px;
padding: 20px;
border: 1px solid #d4edda;
background-color: #e9f7ef;
border-radius: 8px;
font-size: 1.2em;
color: #155724;
text-align: center;
font-weight: bold;
display: none; /* Hidden by default */
}
.first-class-mail-calculator-container #calculationResult.error {
border-color: #f5c6cb;
background-color: #f8d7da;
color: #721c24;
}
.first-class-mail-calculator-container .disclaimer {
font-size: 0.85em;
color: #6c757d;
margin-top: 25px;
text-align: center;
}
First Class Mail Cost Calculator
Use this calculator to estimate the cost of sending your item via USPS First Class Mail within the United States. First Class Mail is an affordable and reliable service for sending letters, flats (large envelopes), and lightweight packages.
Please note: The rates used in this calculator are illustrative examples based on common USPS pricing structures and may not reflect the absolute latest or exact rates. Always verify current rates on the official USPS website for precise pricing.
Letter
Large Envelope (Flat)
Package
Disclaimer: This calculator provides an estimate based on general USPS First Class Mail guidelines and example rates. Actual costs may vary based on specific USPS regulations, current rates, and additional services. Always confirm with USPS for final pricing.
function toggleNonMachinable() { var mailType = document.getElementById("mailType").value; var nonMachinableGroup = document.getElementById("nonMachinableGroup"); if (mailType === "letter") { nonMachinableGroup.style.display = "flex"; } else { nonMachinableGroup.style.display = "none"; document.getElementById("isNonMachinable").checked = false; // Uncheck if not a letter } } function calculateFirstClassMailCost() { var mailType = document.getElementById("mailType").value; var weightOz = parseFloat(document.getElementById("weightOz").value); var lengthIn = parseFloat(document.getElementById("lengthIn").value); var widthIn = parseFloat(document.getElementById("widthIn").value); var thicknessIn = parseFloat(document.getElementById("thicknessIn").value); var isNonMachinable = document.getElementById("isNonMachinable").checked; var resultDiv = document.getElementById("calculationResult"); var cost = 0; var message = ""; var isError = false; // Clear previous results and error states resultDiv.innerHTML = ""; resultDiv.style.display = "none"; resultDiv.classList.remove("error"); // Input validation if (isNaN(weightOz) || weightOz <= 0 || isNaN(lengthIn) || lengthIn <= 0 || isNaN(widthIn) || widthIn <= 0 || isNaN(thicknessIn) || thicknessIn letterMaxWeight) { message = "Your item exceeds the " + letterMaxWeight + " oz limit for a First Class Letter. It may be classified as a Large Envelope or Package."; isError = true; } else if (lengthIn < letterMinLength || widthIn < letterMinHeight || thicknessIn letterMaxLength || widthIn > letterMaxHeight || thicknessIn > letterMaxThickness) { message = "Your item's dimensions (" + lengthIn + "x" + widthIn + "x" + thicknessIn + " inches) are outside the standard First Class Letter size range. It may be classified as a Large Envelope or Package."; isError = true; } else { cost = letterBaseRate; if (weightOz > 1) { cost += Math.ceil(weightOz – 1) * letterAddlOzRate; } if (isNonMachinable) { cost += nonMachinableSurcharge; message = "Includes non-machinable surcharge."; } } break; case "largeEnvelope": if (weightOz > flatMaxWeight) { message = "Your item exceeds the " + flatMaxWeight + " oz limit for a First Class Large Envelope. It will be classified as a Package."; isError = true; } else if (lengthIn > flatMaxLength || widthIn > flatMaxHeight || thicknessIn > flatMaxThickness) { message = "Your item's dimensions (" + lengthIn + "x" + widthIn + "x" + thicknessIn + " inches) exceed the maximum for a First Class Large Envelope. It will be classified as a Package."; isError = true; } else if (thicknessIn > 0.25 && (lengthIn < flatMinLength || widthIn < flatMinHeight)) { message = "Your item's dimensions (" + lengthIn + "x" + widthIn + "x" + thicknessIn + " inches) might be too small for a Large Envelope given its thickness. It could be classified as a Package."; isError = true; } else if (thicknessIn 1) { cost += Math.ceil(weightOz – 1) * flatAddlOzRate; } } break; case "package": if (weightOz > packageMaxWeight) { message = "Your item exceeds the " + packageMaxWeight + " oz limit for First Class Package Service. Consider Priority Mail or other services."; isError = true; } else if (lengthIn > packageMaxLength || widthIn > packageMaxWidth || thicknessIn > packageMaxHeight) { message = "Your item's dimensions (" + lengthIn + "x" + widthIn + "x" + thicknessIn + " inches) exceed the maximum for First Class Package Service. Consider Priority Mail or other services."; isError = true; } else { if (weightOz <= 4) { cost = packageRates.upTo4oz; } else if (weightOz <= 8) { cost = packageRates.upTo8oz; } else if (weightOz <= 12) { cost = packageRates.upTo12oz; } else { // up to 13 oz cost = packageRates.upTo13oz; } } break; } } resultDiv.style.display = "block"; if (isError) { resultDiv.classList.add("error"); resultDiv.innerHTML = "Error: " + message; } else { resultDiv.innerHTML = "Estimated Cost: $" + cost.toFixed(2) + "" + message; } } // Initialize non-machinable checkbox visibility on page load document.addEventListener('DOMContentLoaded', toggleNonMachinable);Understanding First Class Mail
First Class Mail is the most common and economical way to send postcards, letters, large envelopes (flats), and lightweight packages. It's ideal for personal correspondence, bills, invoices, and small merchandise.
Key Characteristics:
- Speed: Generally delivers within 1-5 business days for most domestic destinations.
- Affordability: Often the cheapest option for items under 13 ounces.
- Versatility: Handles various mail types from postcards to small packages.
- Tracking: Available for First Class Package Service, but not typically for letters or flats unless additional services are purchased.
Factors Affecting Cost:
The price of First Class Mail primarily depends on three factors:
- Weight: The heavier your item, the more it will cost. Prices are typically tiered per ounce or per weight range.
- Mail Type/Shape:
- Letters: Standard letters are the cheapest. They must be rectangular, not too thick, and within specific length/height limits.
- Large Envelopes (Flats): These are larger, flexible items like magazines or large documents. They have different size and thickness requirements than letters.
- Packages: Items that are rigid, lumpy, or exceed flat dimensions are classified as packages (parcels) and have higher rates.
- Dimensions: Even within a mail type, exceeding certain length, width, or thickness limits can cause an item to be reclassified (e.g., a letter becoming a large envelope, or a large envelope becoming a package), leading to higher costs. Non-machinable letters (square, rigid, or oddly shaped) incur a surcharge because they cannot be processed by automated equipment.
Using the Calculator:
To get an accurate estimate, select the appropriate "Mail Type" (Letter, Large Envelope, or Package) and enter the precise weight and dimensions of your item. If sending a letter, indicate if it's "Non-Machinable" if it's rigid, square, or has an uneven thickness. The calculator will then provide an estimated cost based on these inputs.