Print sizes in pixels

Last updated: 16 September 2026

To print a picture at a given size and resolution, the image has to be a specific number of pixels. This page lists that number for the common paper sizes, so you can check before exporting rather than discovering the problem on paper.

How the numbers are worked out

Two steps, both simple arithmetic:

Convert to inches. Millimetre sizes divide by 25.4. For example A4 is 210 × 297 mm, so 210 ÷ 25.4 = 8.2677 in and 297 ÷ 25.4 = 11.6929 in.
Multiply by the DPI. width_px = width_in × dpi. At 300 DPI, A4 is 8.2677 × 300 = 2480 px wide and 11.6929 × 300 = 3508 px tall.

Values are rounded to the nearest whole pixel, which is why they are not always exactly divisible.

Paper sizes at common print resolutions

Paper	Physical size	150 DPI	300 DPI	600 DPI
A3	297 × 420 mm	1754 × 2480	3508 × 4961	7016 × 9921
A4	210 × 297 mm	1240 × 1754	2480 × 3508	4961 × 7016
A5	148 × 210 mm	874 × 1240	1748 × 2480	3496 × 4961
A6	105 × 148 mm	620 × 874	1240 × 1748	2480 × 3496
US Letter	8.5 × 11 in	1275 × 1650	2550 × 3300	5100 × 6600
US Legal	8.5 × 14 in	1275 × 2100	2550 × 4200	5100 × 8400
US Tabloid	11 × 17 in	1650 × 2550	3300 × 5100	6600 × 10200
US Half Letter	5.5 × 8.5 in	825 × 1275	1650 × 2550	3300 × 5100

Which resolution to use

150 DPI — acceptable for a poster looked at from a distance. For a coloring page held in your hands, the lines look soft.
300 DPI — the usual target for anything printed and looked at closely, including coloring pages. This is the column to use unless you have a reason not to.
600 DPI — roughly four times the file size for a difference most home printers cannot show. Only worth it for professional output.

Exporting bigger than you need is safe

An image can be printed smaller than its pixel dimensions at no cost in quality. It cannot be printed larger without losing sharpness, because the missing detail is not there to recover. So if you are unsure which size you want, export at the larger one — a 300 DPI A3 file prints fine at A4.

Note on sources

ISO 216 defines the A series: A3 is 297 × 420 mm, A4 is 210 × 297 mm, A5 is 148 × 210 mm, A6 is 105 × 148 mm. Each size is half the area of the one before it.
US sizes follow ANSI/ASME Y14.1 and standard office paper practice: Letter 8.5 × 11 in, Legal 8.5 × 14 in, Tabloid 11 × 17 in, Half Letter 5.5 × 8.5 in.
The pixel values are computed with the formula above, not measured. The 300 DPI values for A4 and US Letter match what AI Coloring Page Generator exports.