Print Sizes Explained: A6, A5, A4 and A3

Print sizes explained

A sizes confuse people because the numbers go the wrong way: the bigger the number, the smaller the print. Each size is exactly half the one before it.

Here are the measurements, and the honest answer to which one to buy.

Posters and prints

A5, A4 and A3 art prints, designed in house and printed in the UK.

Shop posters and prints

The measurements

  • A6 - 105 x 148mm (10.5 x 14.8cm). Postcard size.
  • A5 - 148 x 210mm (14.8 x 21cm). Half a sheet of printer paper.
  • A4 - 210 x 297mm (21 x 29.7cm). Standard printer paper.
  • A3 - 297 x 420mm (29.7 x 42cm). Two sheets of A4 side by side.

Which size for which spot

  • A6 - pinboards, fridges, desks, or as filler in a gallery wall.
  • A5 - shelves, narrow gaps, bedside tables and small kitchens.
  • A4 - the default. Fits the cheapest frames and suits most walls.
  • A3 - above a sofa, bed or fireplace, where anything smaller vanishes.

Frames and mounts

  • A-size frames are stocked by every UK high-street shop, so no custom framing is needed.
  • A mount around an A4 print fills an A3 frame and looks considerably more expensive.
  • Clip frames are cheapest; box frames suit thicker or textured prints.
  • Buy the frame after the print, so you can match it to the room.

A sizes vs inches

  • A4 is close to, but not the same as, 8x10in - a US frame will crop or gap.
  • A3 sits between 11x14in and 12x16in, so use A-size frames if the print is A-size.
  • If a frame is sold in inches, check the aperture rather than the outer size.
  • When in doubt, A4 in an A4 frame is the safe combination.

Shop posters and prints

How to write it so it lands

  • Bigger number, smaller print - each A size is half the one before.
  • A4 in an A4 frame is the safest combination there is.
  • A mount turns an A4 print into an A3-frame piece for a few pounds.

Where to shop next

Frequently asked questions

What size is an A4 print in cm?

A4 is 21 x 29.7cm, the same as a standard sheet of printer paper. A3 is double that at 29.7 x 42cm, A5 is half at 14.8 x 21cm, and A6 is 10.5 x 14.8cm.

Which print size should I buy?

A4 for most walls, A3 above a sofa, bed or fireplace, and A5 for shelves and narrow gaps. If the wall is large, two A4s side by side often work better than one A3.

Will a US frame fit an A4 print?

Not exactly. 8x10in is slightly shorter and wider than A4, so the print will either crop or leave a gap. Use A-size frames, which every UK high-street shop stocks.

Back to blog