A4 Print Size Guide: Exact Dimensions, Frames & Resolution

If you have ever asked what size is an a4 photo print, the short answer is the ISO sheet itself — not a near-A4 inch size.

A4 measures exactly 210 × 297 mm — 21 × 29.7 cm or 8.27 × 11.69 inches. For photo-quality printing you want about 2480 × 3508 pixels at 300 dpi, and you can order exact-A4 prints here.

That millimetre figure is the official ISO 216 size used for paper, frames and portfolios across the UK. It is also the size FreeSnaps prints. Labs that sell “A4” as 8 × 12 inches are offering a different shape, which is why some large prints refuse to sit in an A4 frame.

This guide lists A4 in millimetres, centimetres and inches, explains the A-series ratio, covers pixels and frames, and compares A4 with the inch sizes people mix it up with.

A4 Print Size in Millimetres, Centimetres & Inches

Portrait is the everyday A4 sheet. Landscape is the same sheet turned on its side. These are the figures we print and the same ones shown on our A4 photo prints page.

Unit	Portrait	Landscape
Millimetres	210 × 297mm	297 × 210mm
Centimetres	21 × 29.7cm	29.7 × 21cm
Inches	8.27 × 11.69in	11.69 × 8.27in

Inches are rounded to two decimal places. The millimetre size is the one to trust when you check a product page or a frame specification.

Adobe’s A4 format guide uses the same millimetre, centimetre and 300 dpi pixel figures.

The A4 Aspect Ratio & Why It Matters for Photos

ISO A sizes share one shape: the long side is the short side multiplied by √2 (about 1.414). Halve an A3 sheet parallel to its short edge and you get two A4 sheets. Halve A4 and you get two A5 sheets. The official sizes sit in ISO 216.

Size	Millimetres
A2	420 × 594
A3	297 × 420
A4	210 × 297
A5	148 × 210

Most camera and phone photos are closer to 3:2 or 4:3 than to 1:1.414. A 3:2 holiday snap will not fill an A4 sheet without a crop or a border. That is normal — it is the same reason an 8 × 12 inch print (which is 3:2) looks close to A4 but will not drop into an A4 frame. We unpack that in 8×12 vs A4 print size.

When you upload a photo for A4, preview the crop so faces and important edges stay inside the sheet.

How Many Pixels Do You Need for an A4 Print? (Resolution Guide)

Print sharpness is a mix of file size and viewing distance. Dots per inch (dpi) is how many pixels land in each inch of paper. We print A4 at photo quality and recommend 300 dpi.

Quality	dpi	Pixels	About
Fine for a wall you will not stand next to	150	~1240 × 1754	≈ 2.2 MP
Photo quality (recommended)	300	~2480 × 3508	≈ 8.7 MP

Phone photos at 12 megapixels and above are comfortably above that 300 dpi target. If the short side of your image is under about 1200 pixels, an A4 print will look soft, especially in faces and text. We do not block smaller uploads — you can still print them — but you should expect a gentler, less crisp result.

The pixel figures above are the standard arithmetic for an A4 sheet. They match what designers use in tools such as Photoshop. For the full cheat sheet, including older 5 megapixel files, see how many pixels you need for an A4 print.

What Frame Fits an A4 Print?

Direct fit. A true A4 frame, usually sold as 21 × 30 cm, is made for 210 × 297 mm. IKEA-style A4 frames work the same way, typically without the mount. Frame openings vary by a millimetre or two, so check the listing if you need every edge of the photograph visible.

With a mount / mat. A 30 × 40 cm frame (or a 12 × 16 inch equivalent) with an A4 window mount leaves a border around the print. FreeSnaps framed prints include an 11 × 14 inch frame that holds a true A4 print behind a mount.

Do not assume an “8 × 12” or “large photo print” will fit that 21 × 30 cm opening. An 8 × 12 inch sheet is 203 × 305 mm — 7 mm too long and about 7 mm too narrow. That is the 8 × 12 trap; the 8×12 vs A4 comparison has the table.

A4 vs Other Photo Print Sizes

Inch sizes (4R, 5R, 6R, 8 × 10, 8 × 12) come from older lab catalogues. A4 comes from metric paper. They are easy to confuse in a product name.

Size	Millimetres	Fits a standard A4 frame?
A4	210 × 297	Yes
8 × 12 in	203 × 305	No — too long and too narrow
8 × 10 in	203 × 254	No — shorter on both sides
6R (6 × 8 in)	152 × 203	No — much smaller
5R (5 × 7 in)	127 × 178	No — much smaller
4R (4 × 6 in)	102 × 152	No — much smaller

If you want prints that drop straight into standard A4 frames, the exact 210 × 297 mm size is what matters. A name on a product tile is not enough.

Adobe’s paper sizes guide is a useful primer on why the A series stays in proportion when you step up or down a size.

Frequently Asked Questions

What size is an A4 photo print?

A true A4 photo print measures exactly 210 × 297 mm. That is 21 × 29.7 cm, or about 8.27 × 11.69 inches. Landscape A4 uses the same measurements the other way around.

What is A4 size in cm?

A4 is 21 × 29.7 cm in portrait, or 29.7 × 21 cm in landscape. Shop frames labelled 21 × 30 cm are made for this size.

How many pixels is A4 at 300 dpi?

A photo-quality A4 print at 300 dpi is about 2480 × 3508 pixels, or roughly 8.7 megapixels. That is the size we recommend uploading for a sharp A4 print.

Is A4 the same as 8×12?

No. An 8 × 12 inch print is 203 × 305 mm. A4 is 210 × 297 mm. An 8 × 12 print is too long and too narrow for a standard A4 frame. Read our 8×12 vs A4 guide for the side-by-side measurements.

What frame size do I need for A4?

Use a true A4 frame, usually sold as 21 × 30 cm, for a direct fit. With a window mount, a 30 × 40 cm or 11 × 14 inch frame with an A4 opening works well.

How big is A4 compared to A3 or A5?

A3 is twice A4: 297 × 420 mm. A5 is half of A4: 148 × 210 mm. Each ISO A size keeps the same 1:√2 shape, so two A5 sheets make one A4, and two A4 sheets make one A3.

Print Your Photos at True A4 Size

When you want the sheet that matches UK frames and paper, order A4 photo prints online at FreeSnaps (exact 210 × 297 mm, from £2.10). Prints are made in the UK, in gloss or matt, with a next-day delivery option at checkout.