Free Envelope Size Chart: US Envelope Sizes (#10, A7, Catalog) with What Fits Inside, International DL, C4, C5 and C6 Envelope Sizes, and an Outgoing Mail and Postage Log (PDF, Word, Excel)

What is on the page

#10 envelope

The standard US business envelope, 4 1/8 x 9 1/2 inches, which takes a Letter sheet folded in thirds.

A-style envelopes

US announcement envelopes (A2, A6, A7, A9) for cards and invitations. Not related to ISO A paper sizes.

DL envelope

110 x 220 mm, the standard business envelope for A4 folded in thirds outside North America.

C sizes

ISO envelopes made for A-size paper: C4 for A4 flat, C5 for A5, C6 for A6.

Postage

The cost of sending each item; Excel totals the month so you can compare with your mailing budget.

Choosing US envelopes

For letters and invoices on Letter paper, the #10 is the standard; window #10s show the address printed on the invoice, and a #9 fits inside a #10 as a reply envelope. For cards and invitations, use the A-style announcement envelopes: an A7 fits a 5 x 7 card, an A2 a card made from a Letter sheet folded in four. For documents that shouldn't be folded, such as certificates or contracts, use a 9 x 12 or 10 x 13 catalog envelope. The paper sizes themselves are on the paper size chart.

International envelopes

Outside North America, envelopes are matched to A4 paper. DL is the everyday business envelope for A4 folded in thirds, C5 takes A4 folded in half, and C4 takes A4 flat. The size names follow the paper: a C5 envelope holds A5 paper. Sending a Letter-size document in a DL works too, if it is folded slightly short. For addressing, see the US address guide.

Keeping a mail log

A simple log of outgoing mail answers the questions that come up later: when did we send the invoice, how was the tax return sent, where is the tracking number? It also shows what the office spends on postage each month. Keep the receipts for certified and international mail with the log, and record supplies needed on the supply request form. Postage rates change regularly; check current prices with your postal service.

Editing the files

The charts print ready to use. In Excel, the mail log totals the month's postage automatically.

Questions

What size is a #10 envelope?

4 1/8 x 9 1/2 inches (about 105 x 241 mm). It fits a Letter sheet folded in thirds.

What envelope fits a 5 x 7 card?

An A7 envelope, 5 1/4 x 7 1/4 inches.

What size is a DL envelope?

110 x 220 mm. It holds A4 paper folded in thirds.

What envelope fits A4 paper without folding?

A C4 envelope (229 x 324 mm). In the US, a 9 x 12 or 10 x 13 catalog envelope fits Letter flat.

What is the difference between a #9 and a #10 envelope?

A #9 (3 7/8 x 8 7/8 in) is slightly smaller, so it fits inside a #10 as a return envelope.