Paint quantity estimator

Estimate paint from your wall area, product coverage and coats. Use square metres or square feet, with results in litres, US liquid gallons and Imperial gallons.

Start with your wall area

Use actual wall area, not the room’s floor area. Check coverage and coats on the paint you have chosen.

Area unit

Total wall area (m²)

Add width × height for each wall. Include openings here, then subtract them below.

Doors and windows to exclude (m²)

Optional. Leave blank for 0. Use the same area unit as the walls.

Coverage unit on the product label

Coverage for one coat (m² per litre)

No coverage figure is assumed. If the label gives a range, choose the rate appropriate to your surface; ask the manufacturer if unsure.

Number of coats

Enter the product’s required whole number of coats. Primer and different paint products need separate calculations.

Additional allowance (%) — optional

Your choice, not a recommendation. Blank means 0%. An allowance cannot guarantee there will be enough paint.

Your entries stay in this page, without being saved or sent to our servers. Use a decimal point (1.5), not a decimal comma or thousands separator.

Metric, US and Imperial

One area. Clear quantities.

Enter your areas, chosen coverage and coats to see the same paint estimate in litres, US liquid gallons and Imperial gallons.

Illustrative example40 m² × 2 ÷ 10 = 8 L

With a reader-selected 10% allowance: 8.8 L. The coverage and allowance are examples, not product recommendations.

How much paint does your wall area need?

The estimator subtracts openings from the gross wall area, multiplies by your chosen number of coats, divides by the paint’s coverage for one coat, then adds your optional allowance.

(Wall area − openings) × coats ÷ coverage × (1 + allowance ÷ 100)

Use matching area units first. For a metric example, 45 m² of walls less 5 m² of openings leaves 40 m². At two coats and an entered coverage of 10 m² per litre, that is 8 litres. A selected 10% allowance makes it 8.8 litres. These are software examples, not tested paint coverage.

Measure walls, not the floor

For each rectangular wall, multiply its width by its height in the same unit, then add the wall areas. Add the width × height areas of any doors or windows you want to exclude separately. The tool does not assume room height, opening sizes or that every wall is a rectangle.

Enter metres to calculate square metres, or feet to calculate square feet. For decimal feet, 6 feet 6 inches is 6.5 feet, not 6.6. Irregular surfaces need a suitable measured area. This tool estimates quantities only; it does not provide access, preparation, application or safety instructions.

Match the coverage label, wherever you live

You can enter areas in m² or ft² independently of coverage. Select m² per litre, ft² per US liquid gallon or ft² per Imperial gallon to match the product label. The estimator converts both to compatible units before calculating. US and Imperial gallons are different volumes; the result labels both explicitly.

All result volumes represent the same paint estimate. Do not add the litre and gallon figures together. Changing an input unit clears the affected fields rather than relabelling or approximately converting your measurements.

Conversions use 1 ft² = 0.09290304 m², 1 US liquid gallon = 3.785411784 litres and 1 Imperial gallon = 4.54609 litres. See NIST’s conversion tables. The US value follows the exact 231-cubic-inch gallon definition and 0.0254-metre inch; calculations keep precision until display.

What the estimate leaves out

Coverage is product- and surface-dependent, not a universal constant. Dulux’s paint calculator guidance notes that coverage and coat requirements vary. Use the instructions for the specific paint sold in your region; no manufacturer coverage or coat count is pre-filled here.

This is not a guaranteed purchase quantity. It does not round to local container sizes, include primer automatically or estimate absorption, waste or future touch-ups. An optional allowance is your input, not a recommendation. Check the final amount and container sizes with your supplier or manufacturer.

By HomeMojo Editorial · Paint method v1 · Last reviewed 21 September 2026. Arithmetic tested in software; no product or room test is claimed.

Your entries stay private

Calculations run in your browser, without AI. We do not save or send your entries. If you consent to analytics, we can count a tool start or successful calculation, but never the values or unit choices entered. Read our privacy notice.