Envelope No. 10 paper size
104.775 × 241.3 mm
4.13 × 9.5 inches · 10.48 × 24.13 cm · aspect ratio 1:2.3
What Envelope No. 10 is for
The No. 10 envelope, 4.125 × 9.5 inches, is the standard US business envelope and the one nearly every American window envelope, mail-merge template and printer tray setting assumes. It takes a Letter sheet folded into thirds, which makes it the North American counterpart to DL — and it is 3 mm wider and 21 mm longer than DL, close enough that the two look interchangeable and different enough that a windowed template designed for one shows the address in the wrong place on the other.
Envelope No. 10 in every unit
| Unit | Width | Height |
|---|---|---|
| Millimetres | 104.775 mm | 241.3 mm |
| Centimetres | 10.48 cm | 24.13 cm |
| Inches | 4.13 in | 9.5 in |
| Points (PostScript) | 297 pt | 684 pt |
Envelope No. 10 in pixels
Pixel dimensions depend entirely on the resolution you are working at — there is no single "pixel size" for a sheet of paper.
| Resolution | Pixels | Use |
|---|---|---|
| 72 DPI | 297 × 684 | Screen preview only — far too coarse to print |
| 150 DPI | 619 × 1425 | Draft printing, internal documents |
| 300 DPI | 1238 × 2850 | The standard for commercial print |
| 600 DPI | 2475 × 5700 | Fine detail, line art, archival scanning |
Setting up a print document? Use 300 DPI and add 3 mm of bleed on every edge unless your printer specifies otherwise.
How Envelope No. 10 relates to the rest of the series
About Envelope No. 10
4.125 × 9.5 inches, the standard US business envelope.
Other ISO C series sizes
| Size | Millimetres | Inches |
|---|---|---|
| C4 | 229 × 324 mm | 9.02 × 12.76 in |
| C5 | 162 × 229 mm | 6.38 × 9.02 in |
| C6 | 114 × 162 mm | 4.49 × 6.38 in |
| DL | 110 × 220 mm | 4.33 × 8.66 in |
| C3 | 324 × 458 mm | 12.76 × 18.03 in |
| C7 | 81 × 114 mm | 3.19 × 4.49 in |
| A7 Envelope (US) | 133.35 × 184.15 mm | 5.25 × 7.25 in |
Frequently asked questions
What size is Envelope No. 10 in mm?
104.775 × 241.3 mm.
What size is Envelope No. 10 in inches?
4.13 × 9.5 inches.
What size is Envelope No. 10 in pixels?
There is no single answer — it depends on resolution. At the print standard of 300 DPI it is 1238 × 2850 pixels; at 72 DPI it is only 297 × 684.