A1 size in cm, inches and pixels

A1 size in cm, and in inches and pixels

A1 is A0 folded once. The hub explains how the A series is defined.

What A1 is good for

A1 is poster territory: big enough to hold a wall on its own and read from across a room. It’s the size to choose when the print is the thing you want people to look at, not something that sits politely beside the shelves. At 300 dpi it wants 7016 × 9933 pixels, so check your file against the table above before you commit to it.

How the A series reaches A1

A0 is the whole sheet: 841 × 1189 mm, which is a shade under a square metre and is the only figure in the series anybody had to choose. Everything after it is a fold. Halve A0 across its longer side and you get A1 at 594 × 841 mm, and the thing worth noticing is that the shorter side of A0 has become the longer side of A1 unchanged. That’s the trick the whole series turns on: the proportion is 1 to the square root of 2, the one shape that still has the same proportion after being cut in half.

Most size charts skip this part, and A1 is where it bites hardest. Two A2 sheets side by side are 840 mm across; A1 is 841. That single millimetre puts their combined area at 498,960 mm² against A1's 499,554, so A1 isn’t quite two A2s and A0 isn’t quite two A1s. The shape is preserved and the fit is not. Why that happens to some sizes and not others is on the hub. It still means an image composed for one A size drops onto another without recropping, which is the practical reason the series outlasted its rivals, but if you’re butting two sheets together, that millimetre is real.

Will your file carry A1?

Print size and pixel count are joined by one division: pixels divided by dpi gives you inches. At 300 dpi, A1 wants 7016 × 9933 pixels, which is around 70 megapixels: more than most phones and cameras produce. At 150 dpi the same sheet needs 3508 × 4967, which is well within reach of a good photograph.

That is not a reason to avoid A1. A sheet this size is read from across a room, and the distance does the work that resolution does on a desk print. What matters more is that the original is sharp where it counts: a photograph of a painted figure that was slightly soft at the eyes will be conspicuously soft at A1. The upload step measures your file and withdraws the sizes it can’t print sharply, so you are never offered A1 on a file that will not hold it. The miniature photography guide covers getting the source photograph right in the first place.

A1 against the sizes we print

Nothing in the catalogue is cut to A1, and the nearest thing to it is the 70 × 100 cm poster. That sheet is 106 mm wider and 159 mm taller than A1, and 1.4 times the area, so it isn’t a substitute you can frame in an A1 frame: it is the biggest wall print we make. If you specifically need A1 because you already own the frame, we cannot supply it.

Hanging something A1

An A1 piece is 59.4 cm across and reads from the far side of a room, so it wants a wall to itself and a viewing distance of two metres or more. Framed, it is heavy enough to need two hooks or a picture rail, not a single nail. Unframed, it usually goes up with clips or a hanger strip along the top edge. Anything you print this large shows every soft edge in the file, so check the pixel count above before you choose it.

Check the product size

A product page only lists sizes we print. It tests your file against each one before you order, and a size your image can’t carry is simply not offered.

Size references

The A1 measurements come from ISO 216, the standard for the A and B paper series. For inches we use NIST’s exact inch of 25.4 mm. A1 is a reference here, so look at the print sizes we sell before ordering.

Printing near A1

We don’t print A1. The poster sizes either side of it are 50 x 70 cm and 70 x 100 cm, the largest paper print we sell. See the poster sizes.