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Live USPS postage estimates

USPS Postage Calculator & Mailing Cost Estimator

Estimate postage costs for domestic and international mail. Compare USPS rates for letters, large envelopes, flats, and packages.

Round up to the next ounce; USPS charges by rounded weight.

For a standard #10 envelope, choose 'Letter'.

If you need to send mail online with postage handled for you, you can use our letter mailing service.

What This Postage Calculator Covers

  • Letters, large envelopes, flats, small boxes, and medium boxes.
  • Domestic USPS services including First-Class, Priority Mail, Priority Mail Express, and Ground Advantage.
  • International document envelopes and package estimates for supported USPS international services.
  • Weight-based estimates using rounded ounces, which is how USPS prices many mailpieces.
Certified Mail cost calculator

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This is an independent estimation tool and is not affiliated with, endorsed by, or connected to the United States Postal Service (USPS). USPS® is a registered trademark of the United States Postal Service. All rate estimates are provided for informational purposes only. Always verify current rates at usps.com or at your local post office before mailing.