What Is a Nonmachinable Surcharge?
Your envelope is under one ounce—but it is square, rigid, or has a clasp. That means a $0.35 nonmachinable surcharge, bringing your postage to $1.17.
What Triggers the Surcharge?
| Characteristic | Why |
|---|---|
| Square envelope | Cannot be oriented by sorting machines |
| Landscape address | Address parallel to short side confuses equipment |
| Rigid contents | Does not bend around an 11-inch drum |
| Clasps/strings | Catch in sorting equipment |
| Uneven thickness | Contents like keys or charms create bulges |
Nonmachinable Postage Rates
| Weight | Standard | Nonmachinable |
|---|---|---|
| Up to 1 oz | $0.82 | $1.17 |
| 1-2 oz | $1.11 | $1.46 |
| 2-3 oz | $1.40 | $1.75 |
Have the Right Postage On Hand
Forever stamps and Additional Ounce stamps at discount prices.
Shop StampsFrequently Asked Questions
Do I need the surcharge if I am mailing just one square envelope?
Yes. The surcharge applies per piece, not per batch. Every nonmachinable envelope requires the extra $0.35.
Does a wax seal always trigger the surcharge?
Wax seals can catch in sorting equipment, so the safe answer is yes. Some mailers place the sealed envelope inside a larger outer envelope to avoid the surcharge on the outer piece while protecting the inner seal.
Will the post office return my mail if I do not include the surcharge?
Possibly. Some mail slips through, but USPS is increasingly strict about nonmachinable mail. The safest approach is to include the surcharge when your envelope qualifies.
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.