Two Forever stamps will cover a 2-ounce letter, but you’ll overpay. A 2-ounce First-Class letter costs $1.07 to mail, and two Forever stamps at $0.78 each give you $1.56 in postage. That’s $0.49 more than you need, and the Postal Service doesn’t refund the difference.1United States Postal Service. Notice 123 – January 2026 Price Change For one envelope, that’s a minor cost of convenience. For a stack of wedding invitations or a bulk mailing, it adds up fast.
The math: First-Class letter postage is $0.78 for the first ounce plus $0.29 for each additional ounce, so a 2-ounce letter runs $0.78 + $0.29 = $1.07.1United States Postal Service. Notice 123 – January 2026 Price Change Each Forever stamp is worth whatever the current 1-ounce rate is, which is $0.78 as of January 2026.2USPS. USPS Announces No Stamp Price Changes for January 2026
Cheaper Ways to Hit $1.07 Exactly
One Forever Stamp Plus an Additional Ounce Stamp
USPS sells an additional ounce stamp priced at exactly $0.29, matching the per-ounce charge above the first ounce.3United States Postal Service. Notice 123 – January 2026 Price Change Combine one with a Forever stamp and you get $0.78 + $0.29 = $1.07, no waste. You can buy them at post offices or through the USPS online store.4USPS. Stamps
A Single 2-Ounce Stamp
USPS also sells a 2-ounce stamp, often issued in wedding-themed designs, valued at $1.07 — the exact postage for a 2-ounce letter.5USPS. Wedding Blooms Stamps One stamp per envelope, no math. It stays valid at its printed rate even if prices change later. This is the option people usually reach for on formal invitations, where a single stamp looks cleaner than two.
Is Your Letter Actually 2 Ounces?
A standard #10 business envelope with about four sheets of regular 20-pound, 8.5″ × 11″ paper weighs roughly 1 ounce.6USPS. How to Send a Letter or Postcard Double that, and you’re in 2-ounce territory: roughly eight to ten sheets plus the envelope. Heavier card stock, photo prints, or small enclosures push the weight up faster than plain paper.
A kitchen scale that reads in ounces will confirm it. Any post office will weigh your letter for free. Guessing too light is the mistake to avoid, because underpaid mail either comes back to you or arrives postage-due at the recipient.
When Two Forever Stamps Is the Right Call
If your 2-ounce letter is non-machinable — meaning it can’t run through USPS sorting equipment — a $0.49 surcharge applies on top of the standard rate.1United States Postal Service. Notice 123 – January 2026 Price Change That brings the total to $1.07 + $0.49 = $1.56, which is exactly what two Forever stamps are worth. Non-machinable triggers include square envelopes, rigid contents like a key or USB drive, lumpy enclosures, and clasps or string closures. If any of those describe your envelope, slap on two Forever stamps and you’re covered to the penny.
Size Limits Before Letter Rates Stop Applying
Letter pricing only applies if your envelope is rectangular and no larger than 11½ inches long, 6⅛ inches high, and ¼ inch thick.7Postal Explorer. Sizes for Letters Go over any of those and USPS reclassifies the piece as a large envelope, or “flat.” A 2-ounce flat costs $1.90, not $1.07.3United States Postal Service. Notice 123 – January 2026 Price Change Mailing unfolded 8.5″ × 11″ documents almost always falls into this category.
International Mail Follows Different Rules
Everything above is domestic. For international letters, USPS sells the Global Forever stamp, which covers a 1-ounce letter to any country for $1.70.8USPS. 2026 Postage Price Change A 2-ounce international letter follows a separate schedule that varies by destination, so the math on this page won’t apply. Check with your local post office or the USPS website for the country you’re mailing to.