ISO C series (envelopes)
1/3 A4 paper size
1/3 A4 measures 99 x 210 mm (3.9 x 8.27 in). Part of the ISO C series (envelopes).
Dimensions in every unit
| Unit | Width x height |
|---|---|
| Millimetres | 99 x 210 mm |
| Centimetres | 9.9 x 21 cm |
| Inches (decimal) | 3.898 x 8.268 in |
| Inches (fraction) | 3 7/8 x 8 1/4 in |
| Points (1/72 in) | 280.6 x 595.3 pt |
| Picas | 23.39 x 49.61 pc |
Pixel dimensions by resolution
| Resolution | Pixels | Megapixels |
|---|---|---|
| 72 dpi | 281 x 595 px | 0.2 MP |
| 96 dpi | 374 x 794 px | 0.3 MP |
| 150 dpi | 585 x 1,240 px | 0.7 MP |
| 200 dpi | 780 x 1,654 px | 1.3 MP |
| 300 dpi | 1,169 x 2,480 px | 2.9 MP |
| 600 dpi | 2,339 x 4,961 px | 11.6 MP |
300 dpi is the usual target for printed photos and artwork; 72–96 dpi is screen resolution.
Document size with bleed
| Bleed | Millimetres | Inches |
|---|---|---|
| 3 mm bleed (each side) | 105 x 216 mm | 4.134 x 8.504 in |
| 0.125 in bleed (each side) | 105.4 x 216.4 mm | 4.148 x 8.518 in |
How many 1/3 A4 fit on a press sheet
| Sheet | Without bleed | With 3 mm bleed |
|---|---|---|
| A4 | 3-up | 2-up |
| A3 | 6-up | 4-up |
| SRA3 | 6-up | 6-up |
| Letter | 2-up | 2-up |
| Tabloid 11 x 17 in | 4-up | 4-up |
| 12 x 18 in | 6-up | 4-up |
| 13 x 19 in (Super B) | 6-up | 6-up |
| B2 (offset) | 15-up | 12-up |
| B1 (offset) | 30-up | 27-up |
Simple grid imposition with no gutters or gripper margin; real layouts may fit fewer.
The √2 system
1/3 A4 has an aspect ratio of 1 : 2.1212 — close to √2 (1.4142). Folding or cutting it in half across the long side produces the next smaller size in the series with the same proportions, and two sheets side by side form the next larger size. This is why scaling between sizes in the series (for example on a photocopier) never crops or distorts the page.
This size is listed in the Wikipedia article on paper sizes under “International envelope and insert sizes”. Historic and regional sizes can vary between sources and mills.
Similar sizes
Frequently asked questions
What are the dimensions of 1/3 A4?
How many pixels is 1/3 A4 at 300 DPI?
Sources & data
- Listed in the Wikipedia article “Paper size” (CC BY-SA 4.0).