Two Ounce Stamps Guide: When One Stamp Is Not Enough
When a Two Ounce Stamp Fits
A Two Ounce-category stamp is designed to cover the current postage for a qualifying domestic stamped letter over one ounce through two ounces. It does not make every two-ounce object a letter. Measure the completed piece and check shape, thickness, flexibility, contents, and nonmachinable characteristics.
Two Ounce Stamp or a Combination
At rates effective July 12, 2026, a qualifying two-ounce stamped letter costs $1.11. One ordinary Forever stamp valued at $0.82 plus $0.29 of valid additional postage reaches the same amount. Two ordinary Forever stamps provide $1.64 and overpay by $0.53.
What Happens Above 3.5 Ounces?
A piece over the 3.5-ounce letter maximum must be reclassified, but it does not automatically become a flat. It must satisfy the dimensions, thickness, flexibility, uniformity, and other standards of the next applicable category; some pieces are parcels. Use the completed mailpiece, not weight alone.
Wedding and RSVP Envelopes
Do not assign one ordinary Forever stamp to every RSVP envelope in advance. Assemble the actual reply card and envelope, then check weight, dimensions, rigidity, square shape, closures, and domestic or international destination. A simple qualifying domestic reply envelope may need one ordinary Forever stamp; another design may not.
Frequently Asked Questions
Can I use two ordinary Forever stamps instead of one Two Ounce stamp?
Yes if their combined value meets the required amount, but the stated example overpays.
Does a letter above 3.5 ounces automatically become a large envelope?
No. It leaves the letter category and must meet the standards of the applicable flat or parcel category.
Is one ordinary Forever stamp always enough for an RSVP envelope?
No. Determine postage from the completed reply piece and destination.
After weighing and classifying the complete mailpiece, compare current stamp options that meet the calculated postage amount.
Sources and Scope
- USPS Domestic Mail Manual 101 for letter, flat, and nonmachinable physical standards.
- USPS Notice 123 for current retail prices.
- USPS Postage Price Calculator.
The price example applies only to a qualifying domestic stamped letter at the July 12, 2026 rates.