Paint Calculator - Paint Needed, Quantities & Price

Currency

Every figure below is labelled in the currency you pick. Amounts are not converted — enter your own figures in that currency. To convert an amount at today’s rate, use the currency calculator.

Room length

The longest side of the area, measured in the units shown.

m

Room width

The shorter side of the area, measured at right angles to the length.

m

Wall height

Your height without shoes.

m

Doors

Windows

Coats

How many layers you plan to apply. Two is normal; bare or dark surfaces often need three.

Paint coverage

How much area one unit covers, taken from the product label. Manufacturer figures assume a smooth sealed surface, so bare or textured surfaces need more.

m²/L

Price per litre

The agreed purchase price before tax, fees or any deposit.

$

Paint needed

—

Coverage figures are optimistic

Tins quote coverage on smooth, sealed, previously painted surfaces. Bare plaster drinks the first coat and can cut coverage by 30%; textured walls and dark-over-light changes need more again. The 11 m²/L default is a realistic emulsion figure — check your tin and adjust.

Buy one extra tin, not one less

Batch colours vary slightly between production runs, so the touch-up you do next year will not match if you have to buy fresh. An unopened tin also stores for years, while a second trip mid-job costs an afternoon.

What this page needs from you

This page asks for room length in m, room width in m, wall height in m, doors and windows. Further fields refine the estimate. From those it returns paint needed in L. Every figure updates as you type, and nothing you enter leaves your browser.

Coverage figures are laboratory figures

The area printed on a tin assumes a smooth, sealed, previously painted surface. Bare plaster absorbs the first coat and can cut coverage by about a third; textured walls, and any light colour going over a dark one, need more again. Take the tin's number as the best case.

Buy the extra tin now, not later

Batch colours vary slightly between production runs, so a touch-up bought next year may not match. An unopened tin keeps for years, and a second trip to the merchant mid-job costs an afternoon.

The formula

Litres = (wall area − openings) × coats ÷ coverage per litre

Every result on this page comes from this formula. Nothing is rounded until the final display, so figures match a spreadsheet to the cent.

How to use the Paint Calculator

Fill in each field with your own figures — the defaults are only there as an example.
The result updates as you type, so there is no button to press.
Check the breakdown under the main result for the supporting numbers.
Use the copy button to take the result with you, or share the link to reload the same inputs.

Paint Calculator — frequently asked questions

Is this paint calculator free to use?

Yes. Every calculator on the site is free, needs no sign-up, and runs entirely in your browser, so your figures never leave your device.

How accurate is the result?

The maths is exact for the formula shown on the page. Accuracy in the real world depends on your inputs and on assumptions the formula cannot see, so treat the output as a well-grounded estimate rather than a quote.

Can I use it on my phone?

Yes. The page is responsive, weighs a few kilobytes and works offline once loaded, so it behaves the same on a phone as on a desktop.

What people search for

This page answers each of these searches. They are the exact phrases visitors use to find the paint calculator.

paint calculator

About this calculator

Written and reviewed by The Samsung Calculator editorial team. Every calculator is written against a published formula, reviewed against at least one independent reference implementation, and dated when it changes.

Last reviewed September 10, 2026 · Calculation runs client-side · No data collected · Report an error