Paint Calculator — How Much Paint Do I Need?
A free printable paint calculator. Add as many rooms as your job needs, enter each room's length, width and wall height, subtract the doors and windows, then choose how many coats you are applying and the paint's spread rate in square metres per litre — and the sheet works out the litres and the number of tins to buy for each room and the whole job, with a labelled diagram of every room. Print it or save it as a PDF.
Buying paint is a guessing game if you don't know how much you need — come up short halfway through a wall and the next tin never quite matches, buy too much and half of it dries out in the shed. This calculator takes the guesswork out. You build the job up room by room: for each room you enter its floor length and width and the wall (ceiling) height, and say how many doors and windows to leave out. It works out the paintable wall area — the perimeter multiplied by the height, less a typical allowance for each door and window — and can add the ceiling area too if you are painting that.
The amount of paint then comes from two things: how many coats you are applying, and the paint's spread rate. Spread rate (also called coverage or spreading rate) is simply how many square metres one litre covers in a single coat, and it is printed on every tin — a typical interior wall paint covers around 10 to 13 m² per litre, primers and textured or porous surfaces less. Pick a preset or type the figure from your tin, set the number of coats (most jobs need two), and the sheet multiplies painted area by coats and divides by the spread rate to give the litres required, adds a small touch-up allowance, and rounds up to whole tins in the size you choose.
Every room is drawn on the printable sheet as a simple labelled diagram with its dimensions marked, its wall and ceiling areas listed, and the litres it needs. A totals panel at the top adds the whole job together — total area, litres and tins to buy — and there is a notes area to jot down the colours, brands and finish for each room. Take the finished page to the paint counter and you'll buy exactly what you need.
Printing at exact scale
Every sheet is drawn in real millimetres and prints at exact physical scale. For accurate output, set Scale = 100% (Actual size) and Margins = None in your browser's print dialog. Not sure your printer is honest? Run the printer ruler test first to confirm 50 mm really measures 50 mm. Prefer a file? Use the PDF, PNG or SVG buttons to download the sheet instead of printing — PDF and SVG keep the exact dimensions, and PNG is a 300 DPI image.
Frequently asked questions
How much paint do I need per room?
Enter the room's length, width and wall height and the calculator finds the wall area (perimeter × height), subtracts your doors and windows, multiplies by the number of coats and divides by the paint's spread rate to give the litres for that room. Add the ceiling if you're painting it too.
What is a paint's spread rate?
Spread rate (or coverage) is how many square metres one litre of paint covers in a single coat. It's printed on the tin. Typical interior wall paints are about 10–13 m² per litre; primers, sealers and rough or porous surfaces cover less. Enter the figure from your tin, or use one of the presets.
How many coats should I use?
Most repaint jobs need two coats for an even finish. A big colour change, bare plaster or a dark-over-light job may need three, plus a coat of primer. Set the number of coats and the sheet scales the paint accordingly.
Does it account for doors and windows?
Yes. It subtracts a typical area for each door (about 1.9 m²) and each window (about 1.5 m²) you enter. If your openings are much bigger or smaller, adjust the room size to compensate.
Can I calculate several rooms at once?
Yes — add a room for each space and the sheet lists them all with individual diagrams and paint quantities, then totals the whole job into a single litres-and-tins figure so you know exactly what to buy.
How many tins should I buy?
The sheet divides the total litres (including a touch-up allowance) by the tin size you choose and rounds up to whole tins. Buying one job lot from the same batch helps avoid slight colour differences between tins.
Is the estimate exact?
It's a close estimate. Real coverage varies with the surface, the colour, how thickly you apply it and your roller or brush. Keep the touch-up allowance on, and it's better to have a little spare than to run out mid-wall.
Is it really free?
Yes. Every template on printsheet.io is completely free, with no sign-up, no account and no watermark. Generate as many sheets as you like.
How do I get an exact-scale print?
Choose your paper size, then in the print dialog set Scale to 100% or “Actual size” and Margins to None. The sheet is defined in real millimetres, so it prints at true size. Use the calibration ruler page to verify.
Which paper sizes are supported?
A4, A5, A3, A6, US Letter, Legal and Tabloid, in portrait or landscape. Pick the size that matches the paper loaded in your printer.
Can I save it as a PDF instead of printing?
Yes — choose “Save as PDF” as the printer in your browser's print dialog. The PDF keeps the exact millimetre dimensions.
Can I download it as an image (PNG or SVG)?
Yes — as well as Print and PDF, every sheet has a PNG and an SVG download button. PNG gives you a high-resolution (300 DPI) image at the exact page size, ideal for pasting into a document or sharing. SVG is a scalable vector file that stays razor-sharp at any size and can be edited in tools like Inkscape or Illustrator. Both are generated in your browser from the sheet you see on screen.