No. 10 Envelope vs DL
The No. 10 envelope is 104.8 × 241.3 mm (4.125 × 9.5 in); DL is 110 × 220 mm. DL is 5 mm taller and 21 mm shorter. Each holds its own office sheet folded into thirds: No. 10 for Letter, DL for A4.
| No. 10 envelope | DL | Difference | |
|---|---|---|---|
| Width | 104.8 mm | 110 mm | -5.2 mm |
| Height | 241.3 mm | 220 mm | +21.3 mm |
| Inches | 4.13 × 9.5 in | 4.33 × 8.66 in | |
| Pixels @ 300 dpi | 1,238 × 2,850 | 1,299 × 2,598 | |
| Area | 252.9 cm² | 242 cm² | 104% |
| Aspect ratio | 1:2.3 | 1:2 | |
| Scale to fit | No. 10 envelope → DL: 91% | DL → No. 10 envelope: 95% |
Choose No. 10 envelope when
Use the No. 10 for business mail in the United States and Canada. Letter folded into thirds (216 × 93 mm) fits with room to spare, window versions match US letterhead layouts, and every mailing house stocks it.
Choose DL when
Use DL for business mail in ISO countries. A4 folded into thirds (210 × 99 mm) fits with 5 mm to spare each way, it is the standard window envelope, and it qualifies for the lowest letter rate everywhere.
Which should you use?
Use the envelope that matches the paper. Tri-folded A4 fits a No. 10 with 31 mm of spare length and looks fine. Tri-folded Letter in a DL is a tight fit: the sheet is 216 mm wide against a 220 mm envelope, leaving 2 mm each side, which is below the 3 mm clearance most inserting machines need.
There is no scaling between envelopes, but window positions differ. A Letter designed for a No. 10 window will not show its address through a DL window, and vice versa, so pick the envelope before laying out the letterhead.
Postal rules are the other trap. Both envelopes qualify as standard letters at home, but a No. 10 posted from an ISO country is fine while a DL posted in the US is treated as a normal letter and simply looks unfamiliar.
Questions about this comparison
Is a No. 10 envelope the same as DL?
No. A No. 10 is 104.8 × 241.3 mm (4.125 × 9.5 in); DL is 110 × 220 mm. DL is 5 mm taller and 21 mm shorter. No. 10 is sized for Letter, DL for A4.
Will A4 fit in a No. 10 envelope?
Yes, folded into thirds. A4 tri-folded is 210 × 99 mm, which leaves 31 mm of spare length and 5 mm of spare height inside a No. 10.
Will Letter paper fit in a DL envelope?
Tri-folded Letter is 216 × 93 mm, and DL is 220 × 110 mm, so it fits with only 2 mm of clearance each side. It can be done by hand but jams inserting machines.
Scale one onto the other
The exact percentage for the print dialog, either direction.
Measure it, name it
Not sure which one you have? Type its width and height.