Petrol & Ink

Car poster sizes, and how to pick one.

Five poster sizes, from A4 to 70 by 100 centimetres. The right one depends on the wall and the viewing distance, not on the picture, and it is the decision people most often get wrong in the cautious direction.

The short version. Measure the wall, then buy one size up from the one that feels safe. Undersized art is the commonest mistake in this whole business and it's the one you can't fix afterwards.

SizeIn millimetresBest for
A4210 x 297 mmA desk, a shelf, or a group of three
A3297 x 420 mmA hallway, above a workbench, between two pieces of furniture
A2420 x 594 mmAbove a sofa or a bed: the first size that holds a wall alone
50 x 70 cm500 x 700 mmA stairwell, a garage, a long room
70 x 100 cm700 x 1000 mmA big wall you see from across the room

Your car as art

Once the size and frame are settled, the picture is the easy part: your own car, from one photograph, in the style the room needs.

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The five sizes, in millimetres

Three of them are A-sizes from the international paper series, ISO 216. A4 is 210 by 297 millimetres, A3 is 297 by 420 and A2 is 420 by 594. The pattern is the point: each size is the previous one folded in half across its long side, which works only because every sheet in the series has the same proportions. That is why an A3 is exactly two A4s and why frames for all three are on every high street.

Our manufacturer’s print templates include bleed: extra image around the edges that is trimmed off during production. For the products we sell, A3 arrives as a 305 by 428 millimetre file and A2 as 428 by 602, each carrying four millimetres of bleed on every edge.

The other two are metric and not part of that series: 50 by 70 centimetres and 70 by 100 centimetres. They don't halve into the A-sizes and they're slightly squarer, which matters if you are hanging them next to an A2.

Which one a wall wants

A bare wall above a low leather sofa, with a spirit level and a pencil resting on the sofa arm.
Measure the wall first. The space above a sofa is where A2 starts to earn its place.

A4 is a desk, a shelf, a narrow gap beside a door frame. It's too small to be the only thing on a wall in a normal room, and it is genuinely good in a group of three or more.

A3 is the everyday size: above a workbench, in a hallway, between two pieces of furniture. It also suits a single line on cream, such as 1930: The Roadster, which reads at any size.

A2 is the first size that holds a wall on its own. Above a sofa, above a bed, on the wall you see first walking into a room. It is also the point at which fine detail starts to pay for itself, so a blueprint is worth having at A2 and is a compromise below it.

50 by 70 and 70 by 100 are statement sizes for a wall with distance in front of it: a stairwell, a garage, a long room. The rule of thumb that survives contact with reality is that art above furniture wants to be roughly two thirds of the width of the thing below it, which for a two-metre sofa puts you well past A2.

If you are printing your own photograph

An old film camera on a dry-stone wall, a small parked car soft in the background.
A photograph that is comfortable at A3 can be unusable at A2, so each size is checked on its own.

Resolution is checked against the exact size you order, not in general terms. The working floor is 140 dots per inch at print size, and a size that falls meaningfully below it is refused before checkout instead of apologised for afterwards. The reason it is checked per size, not once is that the same photograph can be comfortable at A3 and unusable at A2.

The other thing worth knowing is that the file is cropped to fit the shape you chose, so the limiting resolution is set by whichever axis has to stretch furthest. A photograph that is much wider than it is tall will lose more than you expect on a portrait size. The custom car art page covers what makes a good upload.

Next

Size settled, the frame is the other half of the decision, and it changes how big the finished object is on the wall. The framing guide takes that on. The formats page covers everything that is not paper.

Written by Craig Fearn, Petrol & Ink. Last updated .

Take it further

Questions, answered

What size is A3 in centimetres?
297 by 420 millimetres, so 29.7 by 42 centimetres. A2 is 420 by 594 millimetres and A4 is 210 by 297.
What car poster size should I buy?
A3 for a hallway, a workbench or a gap between furniture. A2 for a wall you want the print to own, above a sofa or a bed. 50 by 70 or 70 by 100 where there is distance to view it from.
How big should art above a sofa be?
Roughly two thirds of the width of the sofa. For a two-metre sofa that puts you past A2 and into the larger metric sizes.
Why do you not offer A1?
The archival paper we print on is offered at A4, A3, A2, 50 by 70 and 70 by 100 centimetres. 70 by 100 is the largest, and it is close to A1 in area.
Will my photo be sharp enough?
It is checked against the exact size you order, at a working floor of 140 dots per inch at print size, and a size that falls below is refused before you pay. The same photo can pass at A3 and fail at A2.
Two empty frames, one black and one natural wood, each holding a blank sheet that runs edge to edge with no mount.

Next in the wall

How to frame a car print →

A frame is not decoration, it is a decision about how much attention the picture gets. The good news with car art is that the artwork's own ground colour makes most of the choice for you, so there are really only three questions to answer.