Stamp Calculator

Find out exactly how many Forever stamps you need for any letter, postcard, or large envelope.

What are you mailing?

Weight (ounces)Standard letter with 1-4 sheets is about 1 oz.

Or: sheets of paperApproximate, using 20 lb paper + envelope.

Accuracy note: Large-envelope additional-ounce pricing assumes the standard $0.29 per extra ounce. Based on USPS retail prices, January 18, 2026 rates (checked August 2026).

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