How to Calculate Postage Without a Scale
No kitchen scale? Here are five methods to estimate postage.
Method 1: Count Pages
A sheet of paper weighs about 0.16 oz. An envelope: 0.16 oz. So: envelope + 3 sheets = about 0.64 oz (under 1 oz). Envelope + 4 sheets = about 0.80 oz. Envelope + 5 sheets = over 1 oz.
Method 2: Quarter Balance
Five U.S. quarters weigh exactly 1 oz. Balance your envelope against them on a ruler.
Method 3: Thickness Check
If your envelope is thicker than about 6 sheets of paper, it likely exceeds 1 oz.
Method 4: Weigh One at the Post Office
Weigh one fully assembled invitation or card, then stamp the rest at home.
Method 5: Buy a Scale
A $10-15 kitchen scale removes all guesswork. Worth it if you mail regularly.
Frequently Asked Questions
Is the quarter balance method accurate enough for wedding invitations?
For anything important, use a scale. The quarter method gives a rough estimate but is not precise enough for invitations where postage-due would be embarrassing. Weigh one fully assembled invitation at the post office, then use that weight to stamp the rest.
How much does a 5x7 greeting card with envelope weigh?
A standard 5x7 card with a single-layer envelope typically weighs 0.8-1.2 ounces—right at the one-ounce boundary. Adding a photo or thicker cardstock pushes it over. When in doubt, assume it needs extra postage.
Sources and Scope
- U.S. Postal Service — Postal Explorer — Domestic Mail Manual, sections 101 and 201, physical standards for retail letters and cards.
- U.S. Postal Service — Postal Explorer — Notice 123 Price List, First-Class Mail retail prices, effective July 12, 2026.
Rates apply only when the mailpiece qualifies for the stated category. Weight estimates are planning aids, not a substitute for weighing and measuring the finished piece.