Stamp Calculator by Weight

First-Class Mail Postage Calculator by Weight

Calculated Postage for ' + mailTypeName + '

Item Weight:

Estimated Total Postage Cost:

Approximate Number of Standard ($' + standardStampValue.toFixed(2) + ') Stamps Needed:

Note: These rates are examples for First-Class Mail Domestic and are subject to change by USPS. Exact postage may vary based on dimensions, rigidity, and current rates. Always verify with USPS.

Understanding Postage by Weight: Your Guide to Mailing Letters and Flats

Sending mail, especially non-standard items, often requires more than just sticking on a single stamp. The cost of postage is primarily determined by the item's weight, its dimensions, and the mail class you choose. Our First-Class Mail Postage Calculator by Weight helps you estimate the cost for common domestic mail types: standard letters and large envelopes (flats).

How Weight Affects Postage

For First-Class Mail, the United States Postal Service (USPS) uses a tiered pricing structure based on weight. The first ounce (or fraction thereof) incurs a base rate, and each additional ounce (or fraction) adds a specific incremental cost. This means an item weighing 1.1 ounces will cost the same as an item weighing 2 ounces, as both fall into the 'up to 2 ounces' category for pricing.

First-Class Mail Letter (Standard Envelope)

• Dimensions: Typically rectangular, no more than 11.5 inches long, 6.125 inches high, and 0.25 inches thick.
• Weight Limit: Up to 3.5 ounces.
• Pricing Example: The first ounce might cost $0.68, with each additional ounce (up to 3.5 oz) costing an extra $0.24. So, a 2.5-ounce letter would cost $0.68 (for the first ounce) + $0.24 (for the second ounce) + $0.24 (for the third ounce) = $1.16.

First-Class Mail Large Envelope (Flat)

• Dimensions: Larger than a standard letter but no more than 15 inches long, 12 inches high, and 0.75 inches thick. Must be uniformly thick and flexible.
• Weight Limit: Up to 13 ounces.
• Pricing Example: The first ounce might cost $1.39, with each additional ounce (up to 13 oz) costing an extra $0.24. A 5-ounce large envelope would cost $1.39 (for the first ounce) + ($0.24 x 4 additional ounces) = $1.39 + $0.96 = $2.35.

Using the Calculator

Our calculator simplifies this process:

1. Enter Item Weight: Input the weight of your mailpiece in ounces. Use a kitchen scale for accuracy.
2. Select Mail Type: Choose whether you are sending a 'First-Class Mail Letter' or a 'First-Class Mail Large Envelope'.
3. Calculate: Click the "Calculate Postage" button to get an estimated total cost and the approximate number of standard Forever stamps needed.

Important Considerations

• Current Rates: The rates used in this calculator are examples and are subject to change by the USPS. Always check the official USPS website or visit a post office for the most current pricing.
• Dimensions Matter: Even if your item is within the weight limit, if its dimensions exceed the maximum for its mail class (e.g., too thick for a letter), it may be charged at a higher rate or require a different mail class. Non-machinable surcharges can also apply to letters that are oddly shaped or rigid.
• International Mail: This calculator is designed for domestic First-Class Mail. International postage rates are significantly different and depend on the destination country and mail class.
• Packages: For items heavier than 13 ounces or those that don't fit the dimensions of a large envelope, you'll need to use a package service (e.g., First-Class Package Service, Priority Mail), which has different pricing structures often based on weight and shipping zones.

Examples of Use

Let's say you want to mail a few documents:

• Example 1: A standard letter weighing 1.5 ounces.
  • Input: Weight = 1.5 oz, Mail Type = First-Class Mail Letter
  • Output (example): Estimated Total Postage Cost: $0.92 (0.68 for 1st oz + 0.24 for 2nd oz)
• Example 2: A large greeting card with some photos, weighing 4.2 ounces, fitting in a large envelope.
  • Input: Weight = 4.2 oz, Mail Type = First-Class Mail Large Envelope
  • Output (example): Estimated Total Postage Cost: $2.11 (1.39 for 1st oz + 0.24 x 4 additional oz)

By using this calculator, you can get a quick estimate of your postage costs, helping you avoid underpaying or overpaying for your mail.