First-Class Mail® prices are based on size, shape, and weight.
Unusually shaped mail, like square or vertical envelopes, lumpy envelopes, rigid envelopes, and mail with clasps, string, buttons, must be hand-cancelled. They are charged a non-machineable fee even if they weigh less than 1 ounce.
If a mailpiece exceeds the maximum length or height or thickness, it will be charged at the next higher price or mailpiece category.
Large envelopes (or flats) that exceed maximum dimensions, or are rigid, are charged parcel prices.
Price Calculator Wizard
Sound complicated? The USPS Price Calculator wizard will show how to measure your envelope and then calculate your domestic postage costs for you!Calculate a Price First-Class Mail Prices
- Best priced service for mail up to 13 oz
- Delivery in 1 to 3 business days
- Insurance for loss or damage up to $5, 000 for merchandise only
- Can combine with extra services to confirm delivery