Wall Art Size Calculator

How the artwork size calculator works

Three numbers do almost all the work: the width of whatever stands under the wall, the height of that furniture, and eye level. Everything the calculator returns is derived from those, so the result is reproducible rather than a matter of opinion.

For a sofa, bed or sideboard the tool takes 70 per cent of the furniture width and rounds to the nearest 5 cm. That sits inside the two-thirds-to-three-quarters band that galleries and interior designers use, and it is the single most reliable rule in the whole exercise: art narrower than two-thirds of the furniture reads as an afterthought, art wider than the furniture reads as a mistake. Height is then derived as width divided by 1.5, a 3:2 landscape. The bottom edge is placed 20 cm above the furniture, using 85 cm for a sofa back, 115 cm for a headboard and 88 cm for a sideboard, and the hanging centre falls out of that. If the resulting top edge would come within 20 cm of the ceiling, the height is trimmed instead of the rule being broken.

An empty wall is calculated differently, because there is nothing to relate the artwork to. Here the width is 57 per cent of the wall width, the centre is pinned to 147 cm — museum and gallery hanging height, set at the average adult eye level — and the height is 75 per cent of the width, a 4:3 format that suits a wall with no horizontal line beneath it. The height is clamped so the top stays 25 cm below the ceiling and the bottom edge never drops below 55 cm.

Choosing a pair or a triptych keeps the same total width. The tool divides that total by the number of pieces, subtracts 6 cm gaps, and for three pieces drops the height to 92 per cent of the single-piece figure, which stops a row of three from looking top-heavy. The important part is conceptual: a group hangs as one block, so you centre the block, not the middle picture.

A worked example

Say you have a 220 cm sofa, a 380 cm wall and a 250 cm ceiling. Seventy per cent of 220 is 154, which rounds to 155 cm of artwork. The height becomes 155 divided by 1.5, or 103, rounded to 105 cm. The sofa back is 85 cm, plus the 20 cm gap, so the bottom edge sits at 105 cm from the floor and the centre lands at about 158 cm. The top edge reaches 210 cm, leaving 40 cm of clear wall below the ceiling, so nothing needs trimming. Split the same 155 cm into a triptych and you get three panels of roughly 50 cm with 6 cm between them — which, usefully, is a far easier set of frames to find in stock than one 155 cm piece.

Run the same wall as an empty wall instead and the answer changes completely: 57 per cent of 380 is 215 cm wide, 160 cm high, centred at 147 cm. That is not a contradiction. It is the honest consequence of having no furniture to anchor the composition.

When to break the rule

The two-thirds convention is a convention, not physics. Four situations justify overriding it. A tall, narrow wall wants a portrait format, so swap the ratio and keep the centre. A work with a wide mount should be measured by its framed outside dimensions, not the image — a 50 cm print in an 80 cm frame is an 80 cm artwork. A piece that is mostly empty field can go larger than the rule suggests without crowding anything, because most of its surface is quiet; that is the argument in negative space in art, and it is the one case where oversizing almost always improves the room. And a staircase or corridor is seen in motion, so eye level drifts: hang to the line people walk, not to a fixed 147 cm.

Two practical notes before you drill. The hanging hardware sits below the top edge, so the nail usually goes 5 to 10 cm lower than the frame top, and heavy work on plasterboard needs a fixing rated for the weight rather than a picture hook. Once you have a target size, test it against the actual room in the artwork size visualizer rather than trusting a tape measure outline on the wall. If you are still choosing what to hang, the art style quiz narrows the field, and collecting minimalist art covers editions, condition and the paperwork worth insisting on.