Introduction
A statement envelope holds a printed bill or account statement, and its size is dictated by two things: the sheet it must carry and the postal rate class it must stay inside. Get the size wrong and the statement either folds awkwardly or the piece tips into a higher postage tier.
This guide covers statement envelope dimensions only — the #10 double-window standard, the #9 reply, the 6¾, and the international DL — along with the window alignment rules that keep a form-driven statement machine-readable. For the workflow around statements (processing, remittance handling, reply design), see our statement and remittance envelopes guide.
The Standard Statement Size
In North America, the statement envelope is the #10. It carries a letter-size sheet folded in thirds.
| Envelope | Dimensions | Carries |
|---|---|---|
| #10 | 4⅛” × 9½” | 8½ × 11 sheet, tri-folded |
| #9 | 3⅞” × 8⅞” | Reply slip, nests in #10 |
| 6¾ | 3⅝” × 6½” | Small statement, check |
| DL | 110 × 220 mm | A4 tri-folded (international) |
The #10 dominates because a standard sheet folds to fit it exactly.
| Reason | Why It Matters |
|---|---|
| Sheet fit | 8½ × 11 tri-folds cleanly |
| Postage class | Stays inside the letter rate |
| Availability | Cheapest and most stocked size |
| Machine handling | Standard dimensions for inserters |
#10 Statement Envelope Dimensions
The #10 is specified in inches across North America and in millimetres internationally.
| Measure | #10 Value |
|---|---|
| Width | 4⅛” (4.125 in / 104.8 mm) |
| Length | 9½” (9.5 in / 241.3 mm) |
| Standard insert | 8½ × 11 folded in thirds |
| Flap | Commercial or wallet |
A double-window #10 adds two die-cut openings on the front face:
| Window | Position | Shows |
|---|---|---|
| Address window | Lower left / center-left | Recipient address |
| Return window | Upper left | Sender return address |
| Both align | To one printed form | No separate addressing needed |
The window positions are not arbitrary — they are set so the printed statement’s field positions line up underneath them. When the form moves, the windows must move with it.
#9 Reply Envelope Dimensions
The #9 is the reply vehicle. Its size is chosen so it nests inside a #10 without folding.
| Measure | #9 Value |
|---|---|
| Width | 3⅞” (3.875 in / 98.4 mm) |
| Length | 8⅞” (8.875 in / 225.4 mm) |
| Fit | Slips inside a #10 |
| Purpose | Payment return, reply |
Because it fits inside the outgoing envelope, the #9 lets a statement carry a return envelope without adding a fold step or exceeding the letter rate.
| Use | #9 Role |
|---|---|
| Bill with payment slip | Reply vehicle |
| Donation appeal | Reply vehicle |
| Survey | Reply vehicle |
6¾ Envelope Dimensions
The 6¾ is the compact statement and check envelope.
| Measure | 6¾ Value |
|---|---|
| Width | 3⅝” (3.625 in / 92.1 mm) |
| Length | 6½” (6.5 in / 165.1 mm) |
| Carries | Check, small statement, remittance slip |
| Fit | Letter folded in quarters |
It suits mailings where the contents are small — a paycheck, a single remittance slip — and a full #10 would look empty.
DL Envelope Dimensions (International)
For UK, EU, and Australian billing, the statement envelope is the DL format, which maps to A4 paper rather than US letter.
| Measure | DL Value |
|---|---|
| Width | 110 mm |
| Height | 220 mm |
| Carries | A4 sheet folded in thirds |
| US equivalent | Close to #10 in proportion |
Choosing between a US and international statement size is a decision about the paper the bill is printed on.
| Paper Standard | Statement Envelope |
|---|---|
| US Letter (8½ × 11) | #10 |
| A4 (210 × 297 mm) | DL |
Window Position and OCR Alignment
A statement envelope’s window is a functional aperture, not a design feature. It must sit exactly over the address field of the printed form.
| Rule | Requirement |
|---|---|
| Address block placement | Must match the window position exactly |
| Window size | Address fully visible, with clearance |
| Clear zone | Nothing printed inside the address window area |
| Machine readability | Address font and contrast must suit OCR |
Small misalignments matter more than they appear, because automated sorters read the address through the window:
| Problem | Consequence |
|---|---|
| Window shifted | Address partially cut off, falls to manual handling |
| Address moved on the form | Window shows blank paper |
| Print inside the clear zone | OCR misreads the address |
| Low contrast | Sorting errors |
For the full window geometry specification, see our window envelope design standards guide.
Size and Postage Class
Statement size determines which postal class the piece falls into, which determines its cost.
| Class | Typical Limits | Statement Impact |
|---|---|---|
| Letter | Up to 6⅛” × 11½” | #10 and DL stay here |
| Large envelope / flat | Above letter, to 12″ × 15″ | Larger statements move here |
| Parcel | Beyond flat limits | Rarely relevant for statements |
The practical rule is to keep the statement inside the letter class:
| Goal | Action |
|---|---|
| Lowest postage | Use #10 with a tri-folded sheet |
| Avoid a class jump | Do not exceed the letter size or thickness limit |
| Verify before the run | Weigh a finished sample |
A statement that grows past the letter limits — a thicker insert, a second sheet, a heavier reply envelope — can quietly move the whole mailing into a higher rate.
Choosing the Right Statement Size
| Situation | Envelope |
|---|---|
| Standard bill, US letter | #10 |
| Bill with payment reply | #10 with #9 enclosed |
| Compact statement or check | 6¾ |
| A4 billing, international | DL |
| Multi-page statement | Larger flat — but watch the class jump |
The decision follows the sheet: match the envelope to the paper standard, then confirm the folded thickness keeps the piece inside the letter rate.
Conclusion
Statement envelope size comes down to four dimensions — #10 at 4⅛ × 9½ inches for standard US billing, #9 at 3⅞ × 8⅞ inches as its reply companion, 6¾ at 3⅝ × 6½ inches for compact statements and checks, and DL at 110 × 220 mm for A4 billing. Match the envelope to the paper standard, align any window exactly to the address field for OCR readability, and verify the finished thickness stays inside the letter rate.
For the processing side of statement mail — remittance handling, reply design, and Business Reply Mail — see our statement and remittance envelopes guide, or the broader billing envelopes overview.
Need statement envelopes in a specific size and window layout? Request a quote and we will match the spec to your form.