Custom #9 Envelopes (3 7/8″ x 8 7/8″)

A #9 envelope measures 3 7/8" x 8 7/8" (3.875" x 8.875").

Yes. A #9 fits inside a standard #10 (4 1/8" x 9 1/2") without folding, which is why it's the most common return envelope.

A #10 is 1/4" taller and 5/8" wider. Use #10s for outgoing mail and #9s as the reply envelope inside.

Mostly return and remittance mail, such as bill payments, donations, RSVPs and signed forms.

Yes, a letter folded in thirds fits, though more snugly than in a #10. For multi-page letters, a #10 works better.

Yes. A standard address window is available. Window envelopes are ideal when your remit-to address is printed on a payment coupon or reply card.

Yes, through a custom quote. You'll need a USPS Business Reply Mail permit.

Choose 1–2, 2–4 or 5–7 business day production, depending on quantity.

Yes. Choose full color on both sides, or front printing plus back-flap printing for a thank-you message, website or reply instructions.

Yes. Variable address printing can add a unique customer name, return address, account number or donor ID to each envelope, so replies are easy to match to accounts.

Please send your mailing list as a CSV file (.csv). You can build it in Excel or Google Sheets, then choose File → Save As (or Download) → CSV.

Your CSV needs one header row followed by one recipient per row. Label the header columns exactly as follows:

• Column A: FULL NAME
• Column B: COMPANY
• Column C: ADDRESS
• Column D: SUITE/APT
• Column E: CITY STATE ZIP CODE

Just leave that cell blank, but keep the column in your file. All five columns (A to E) should be present in every list, even if some cells are empty.

No. Put the city, state and ZIP code together in column E, for example "GLENDALE CA 91202". Don't split them into separate columns.

Yes. We print each address exactly as it appears in your file, so check spelling, apartment numbers and ZIP codes before you upload. For best delivery results, USPS recommends all capital letters with no punctuation.

Excel sometimes drops the leading zero from ZIP codes like 02108 (Boston), turning them into 2108. Before saving, format column E as Text, or double-check any ZIP codes that start with 0.

No. The faster 1–2 business day turnaround isn't available for variable addressing orders. Your envelopes are produced on our standard turnaround, so plan your mailing date accordingly.

Yes. Variable addressing is a paid add-on, and the price depends on your order quantity. Select variable addressing in the price calculator to see your exact total before you check out.

Yes. We'll print any address you provide in the format above. Most customers mail to U.S. addresses, but for an international recipient, put the city, postal code and country together in column E (CITY STATE ZIP CODE).

Order at least as many envelopes as there are names on your list. Many customers add a few extra blank envelopes for last-minute additions or mistakes.

---