A4 size in cm, inches and pixels
A4 size in cm is 21 × 29.7, which is 210 × 297 mm and 8.27 × 11.69 inches.
Shopping for a frame? Check the exact opening in millimetres. A-series paper is a different shape from US Letter (8.5 × 11 inches) and Tabloid (11 × 17 inches). A paper-size reference does not mean every size is sold in our store.
A4 is 210 × 297 mm, which is 21 × 29.7 cm and 8.27 × 11.69 inches.
A4 size in cm, plus inches and pixels at each dpi
| Millimeters | 210 × 297 mm |
|---|---|
| Centimeters | 21 × 29.7 cm |
| Inches | 8.27 × 11.69 in |
| Pixels at 72 dpi | 595 × 842 px |
| Pixels at 150 dpi | 1240 × 1754 px |
| Pixels at 300 dpi | 2480 × 3508 px |
A4 is A0 halved four times, and the unit every other size gets described against. How the A series is defined is on the hub.
How the A series reaches A4
Four halvings from the top. A0 measures 841 × 1189 mm; the cuts give A1 at 594 × 841, A2 at 420 × 594, A3 at 297 × 420 and then A4 at 210 × 297. The inherited side never changes, but the halved side is rounded down at every step - 1189 to 594, 841 to 420, 297 to 148 - which is why some of these sizes double exactly and some do not.
That behaviour belongs to 1:√2 and to no other ratio, which is why the series uses it. A4 covers 62,370 mm² and is exactly half an A3: two A4 sheets make 124,740, which is an A3 to the millimetre. Going the other way it is not exactly twice A5 — two A5s fall 210 mm² short of it, and the hub says why. The exact half is the reason the office photocopier enlarges A4 to A3 on one button with nothing falling off the edge.
Will your file carry A4?
Pixels divided by dpi gives inches, so a size's pixel requirement is just its width in inches multiplied back up. A4 at 300 dpi is 2480 × 3508 pixels, about 8.7 megapixels — a bar almost any phone from the last decade clears. At 150 dpi it is 1240 × 1754.
Check the US product size
Compare the available sizes and prices before ordering. Free UK delivery is included in every price.
Size references
ISO 216 defines the A and B paper-size series. Inch conversions use NIST’s exact definition of one inch as 25.4 mm. These are reference sizes; compare the print sizes actually available before ordering.
Pixel and print-size converter
| Size | Millimetres | 72 dpi | 150 dpi | 300 dpi |
|---|---|---|---|---|
| A1 | 594 × 841 mm | 1684 × 2384 px | 3508 × 4967 px | 7016 × 9933 px |
| A2 | 420 × 594 mm | 1191 × 1684 px | 2480 × 3508 px | 4961 × 7016 px |
| A3 | 297 × 420 mm | 842 × 1191 px | 1754 × 2480 px | 3508 × 4961 px |
| A4 | 210 × 297 mm | 595 × 842 px | 1240 × 1754 px | 2480 × 3508 px |
| A5 | 148 × 210 mm | 420 × 595 px | 874 × 1240 px | 1748 × 2480 px |
Pixels ÷ dpi gives inches, and that is the whole calculation. Three hundred dpi is a convention for things held close, not a rule; a print read from across a room is untroubled at 150. Every size above is worked from the ISO 216 definition — A0 is 841 × 1189 mm and each size halves the longer side, rounded down to whole millimetres.
Good to know
What size is A4 in cm?
A4 is 21 × 29.7 cm, or 210 × 297 mm.
What is A4 in inches?
8.27 × 11.69 inches.
How many pixels is A4 at 300 dpi?
2480 × 3508 pixels. At 150 dpi it is 1240 × 1754, and at 72 dpi 595 × 842.
Is A4 bigger than A5?
Yes, by a little over double: 62,370 mm² against 31,080. Half of 297 mm is 148.5 and ISO 216 rounds A5 down to 148, so two A5 sheets come 210 mm² short of an A4.
