First-Class Postage Calculator
First-Class postage from piece type, weight, and machinability at retail rates.
What it does
First-Class retail pricing turns on three facts: the piece type, the weight rounded up, and whether machines can sort it. A 2 oz letter costs $1.11 while the same weight as a flat costs $2.27, so naming the piece correctly saves real money.
The tool above takes piece type, weight, and machinability. It returns the postage, the line by line breakdown, and the applicable weight limit.
The default 2 oz stamped letter totals $1.11 from $0.82 plus one $0.29 ounce. A 3 oz flat by the same math totals $2.27, and a rigid 1 oz letter totals $1.31 with the surcharge.
Rates follow official USPS pricing pages with the July 2026 price release behind them. Both pin the $0.82 letter, $0.65 card, and $1.69 flat figures used here.
How to use
- Pick the mailpiece type.
- Enter the weight in ounces.
- Flag nonmachinable shapes.
- Read the postage first.
- Read the breakdown beside it.
- Check the weight limit tip.
Formula
- piece
- Stamped, metered, postcard, or flat.
- weight
- Actual weight, rounded up per ounce.
- nonmachinable
- $0.49 letter surcharge when rigid or square.
- limits
- 3.5 oz letters, 13 oz flats.
Weights round up to whole ounces for extra counts. Letters cap at 3.5 oz, flats at 13 oz and 3/4 in thick. Rates are July 2026 retail; confirm at USPS before mailing, since prices move yearly.
Worked example
Example: 2 oz stamped letter
Defaults: stamped letter, 2 oz, machinable.
- Piece: stamped letter, 2 oz, machinable.
- First ounce: $0.82.
- Extra: ceil(2) - 1 = 1 oz x $0.29 = $0.29.
- Total: 0.82 + 0.29 = $1.11.
- Limit check: 2 oz sits under the 3.5 oz letter max.
- Tool shows $1.11, first oz $0.82 + 1 x $0.29.
Reference table
| Piece | First oz | Next |
|---|---|---|
| Postcard | $0.65 | Letter rate if oversize |
| Letter stamped | $0.82 | +$0.29 / oz to 3.5 oz |
| Letter metered | $0.78 | +$0.29 / oz to 3.5 oz |
| Flat | $1.69 | +$0.29 to 8, $0.30 to 11, $0.31 to 13 oz |
| Nonmachinable | +$0.49 | Letters only |
Limits
- Retail single piece only; commercial rates differ.
- Prices move yearly, confirm before mailing.
- Thickness and size rules sit beside weight.
- International mail uses other charts.
Common mistakes
- Weighing without the envelope.
- Mailing square invites without the surcharge.
- Stuffing past 3/4 in as a flat.
- Using postcard rate for oversize cards.
- Trusting last year prices.
Try it yourself
Quick checks. Answers sit tucked under each question.
Single postcard?
Flat $0.65, within card size rules.
1 oz metered letter?
First ounce metered $0.78, no extras.
1 oz rigid square letter?
$0.82 + $0.49 = $1.31.
Questions
What does a postcard cost?
$0.65 at retail. Oversize cards pay the letter rate instead.
What does a letter cost?
$0.82 stamped, $0.78 metered for the first ounce, then $0.29 per extra ounce to 3.5 oz.
What does a large envelope cost?
$1.69 first ounce, then $0.29 to 8 oz, $0.30 to 11 oz, $0.31 to 13 oz.
What is the nonmachinable surcharge?
$0.49 on letter size pieces that are square, rigid, lumpy, or clasped.
Do Forever stamps still work?
Yes. Forever stamps always cover the current 1 oz letter rate, metered mail needs exact postage.
What if my envelope is too heavy?
It goes as a flat from $1.69, or as a package past 13 oz and 3/4 in thick.