Paint calculator
Calculate the paint you need for walls and ceilings: the area to cover (doors and windows deducted), the number of coats and the product yield give the litres and the tins to buy. A litre covers roughly 8 to 12 m², a room usually wants two coats, and a 10 % margin spares you a second trip to the shop. A shopping list is a private figure, worked out on your device.
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- Free · no account
- Instant result
This tool runs entirely in your browser — nothing is sent to a server.
The amount of paint needed depends on three factors: the surface to cover (walls: perimeter × height, minus doors and windows), the number of coats (two in general) and the product yield, stated on the tin (8 to 12 m²/L per coat depending on quality).
This calculator gives the litres needed and the number of tins to buy (2.5 L or 10 L). Allow a margin of about 10 % for touch-ups, and an extra coat on a porous, new or dark-coloured surface.
How it works
Type the figures or drop the file you want to process — the tool checks them as you go.
Everything is computed directly in your browser. Nothing is sent to a server.
The result appears instantly, with the detailed breakdown ready to copy, download or keep.
Why use this tool
No account, no download, no limit: the result appears as soon as you enter your data.
Every rule, algorithm and check reflects what we use ourselves every day at Flexina.
The calculations follow the official standards, and the step-by-step detail lets you double-check the outcome.
What does running it locally bring you?
Files, figures and documents never leave your device: nothing is stored, nothing is sent.
Once the page is loaded, you can cut the network: the tool keeps working.
No upload, no account, no third-party server in between: results stay fast and fully private.
Frequently asked questions
How many coats should I plan for?
Two in most cases. One may suffice with a high-end paint on a close shade; three are sometimes needed to cover a dark colour or new plaster (after a primer).
Is the yield stated on the tin reliable?
It is a theoretical yield on a smooth, prepared surface. On a rough or porous surface, or with a long-nap roller, count 10 to 20 % less.
Should I deduct doors and windows?
Yes: about 1.6 m² per door and 1 to 2 m² per window. The calculator’s dedicated field handles it.