Paint Calculator
Calculate how many litres of paint you need to cover walls, ceilings, or a room. Accounts for doors, windows, coats, and paint coverage rate.
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How to use this calculator
Net area = total wall area minus doors and windows. Coverage rate is typically 10–14 m² per litre for standard interior paint.
- 1
Enter the room dimensions and ceiling height.
- 2
Enter the number of doors and windows to subtract from paintable area.
- 3
Set the number of coats (2 is standard for good coverage) and your paint's coverage rate (check the tin — typically 10–14 m²/L).
Frequently asked questions
How much does one litre of paint cover?
Standard interior emulsion typically covers 10–14 m² per litre per coat on a smooth surface. Rough or porous surfaces absorb more paint and reduce coverage to 8–10 m²/L. Always check the product specification on the tin.
How many coats of paint do I need?
Two coats are standard for most interior repaints. If changing from a dark to a light colour, or painting new plaster, three coats may be needed. Primer + 2 topcoats is the professional standard for new surfaces.
Should I buy extra paint?
Yes — add 10–15% to allow for touch-ups, uneven application, and future repairs. Also, identical paint mixed later may not match perfectly, so buy your full requirement in one batch.
Paint Calculator — Litres Needed for Walls & Ceilings
How to use the paint
Use this paint to how many litres of paint you need to cover walls, ceilings, or a room. Enter your values above and get your result in seconds. The tool is free, works on all devices, and keeps your data private — nothing is stored or shared.
How the paint works
The paint calculator uses standard formulas used in building projects, renovation planning, and material ordering. Enter your inputs, and the tool calculates the result instantly in your browser. No server-side processing means your data stays on your device. Results update in real time as you change inputs.
Types of interior paint
Matt/flat: hides surface imperfections, not washable — use on ceilings and feature walls. Eggshell/satin: slight sheen, more durable and washable — ideal for living rooms and bedrooms. Semi-gloss/gloss: highly durable and washable — best for kitchens, bathrooms, and trim.
Tips for a professional finish
Clean and repair surfaces before painting. Use painter's tape for crisp edges. Apply paint in a "W" pattern with a roller, then fill in without lifting the roller. Cut in edges with a brush first. Apply the second coat only after the first is fully dry (check the tin for recoat time — typically 2–4 hours).
Paint: how it works
Construction estimation tools save time and reduce material waste by calculating exact quantities before you buy. This tool uses standard industry formulas for accurate estimates across common building and renovation tasks.
Who uses this tool?
Contractors, DIY homeowners, quantity surveyors, and architects use it to generate material lists before requesting quotes. It supports better project planning and reduces the risk of costly underestimates.
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Results are estimates for informational purposes only and do not constitute professional financial, medical, legal, or technical advice. Read full disclaimer →