A4 Size: Dimensions in cm, mm and Inches

A4 is 210 × 297 mm, which is 21 × 29.7 cm or 8.3 × 11.7 inches. It's half the size of A3 and twice the size of A5, and it's the standard paper size for letters and documents everywhere except North America. Framed, an A4 print comes out at roughly 25 × 34 cm to 31 × 40 cm on the wall.

Below you'll find A4 in every unit, how it differs from US Letter and the other sizes it gets confused with, and how big it looks once it's framed.

A4 dimensions in every unit

Unit	Width × height (portrait)
Millimetres	210 × 297 mm
Centimetres	21 × 29.7 cm
Inches	8.3 × 11.7 in (8.27 × 11.69 to two decimals)
Area	0.0625 m², one sixteenth of a square metre

In landscape it's 297 × 210 mm. The shape stays the same.

A4 compared with the other A sizes

Each A size is exactly half the one above it, and they all share the same shape, so a design can be scaled from A4 up to A3 or down to A5 without cropping.

Size	Millimetres	Compared with A4
A5	148 × 210	Half of A4
A4	210 × 297	-
A3	297 × 420	Twice A4
A2	420 × 594	Four times A4
A1	594 × 841	Eight times A4
A0	841 × 1189	Sixteen times A4

A4 vs US Letter, and other lookalikes

These sizes are close to A4 but won't fit an A4 frame properly.

Size	Centimetres	Difference from A4
US Letter (8.5 x 11 inches)	21.6 × 27.9	0.6 cm wider, 1.8 cm shorter
9 x 12 inches	22.9 × 30.5	1.9 cm wider, 0.8 cm taller
20 x 30 cm	20 × 30	1 cm narrower, 0.3 cm taller
10x8 inches	20.3 × 25.4	0.7 cm narrower, 4.3 cm shorter, and a different shape

US Letter is the one that catches people out. It's a little wider and noticeably shorter than A4, so a Letter print leaves a gap at the top and bottom of an A4 frame. Our picture frame size chart covers the other common sizes.

A4 in pixels, for printing

Resolution	A4 in pixels (portrait)
300 ppi (high quality)	2480 × 3508 px
150 ppi	1240 × 1754 px
72 ppi (screen only)	595 × 842 px

300 ppi is the usual target for a sharp print at A4, because it's a size people look at up close. Our pixels to print size calculator will check a specific file.

How big an A4 print looks framed

Moulding width	Outside size of an A4 frame
Slim, 20 mm	About 25 × 33.7 cm
Medium, 35 mm	About 28 × 36.7 cm
Wide, 50 mm	About 31 × 39.7 cm

A single A4 frame suits a desk, a shelf, a narrow wall or a spot beside a door. On a larger wall it works best in a group, such as a grid of four or six, or as part of a gallery wall. A mount makes an A4 print look much more substantial.

Which frame for an A4 print?

The look you want	Frame	Mount border
Print fills the frame, no mount	A4 frame	None
A4 print with a mount	A3 frame	About 4.4 cm at the sides, 6.2 cm top and bottom
A4 print with a mount, more even	30 x 40 cm frame	About 4.5 cm at the sides, 5.2 cm top and bottom
A5 print with a mount, in an A4 frame	A4 frame	About 3.1 cm at the sides, 4.4 cm top and bottom

For an exactly even border, our custom-cut mounts can be made to any width.

See it before you buy. On any of our A4 frames, tap Preview Your Own Artwork and upload a photo of your print to see it in the frame.

Common questions

How big is A4 in cm?

21 × 29.7 cm.

What is A4 size in inches?

8.3 × 11.7 inches (8.27 × 11.69 inches to two decimal places).

Is A4 the same as US Letter?

No. US Letter is 8.5 × 11 inches (21.6 × 27.9 cm), slightly wider and 1.8 cm shorter than A4.

Is A4 bigger than A5?

Yes, A4 is twice the size of A5. Fold an A4 sheet in half and you get two A5s.

What size frame do I need for an A4 print?

An A4 frame if you want the print to fill it. For a mount, an A3 frame or a 30 x 40 cm frame.

What size is A4 in pixels?

2480 × 3508 pixels at 300 ppi, or 1240 × 1754 pixels at 150 ppi.

More size guides: A3 size, A5 size and the full picture frame size chart.

Browse our A4 picture frames, handmade to order by Guild Certified Framers.