Trade & Construction

Paint Coverage Calculator

Trade & Construction

Paint Coverage Calculator

Live answer5.68 L25.8 m² paintable · 51.6 m² coated across 2 coats

Total wall length (m)Add the widths of the walls being painted.Wall height (m)Use the average paintable height.Doors/windows to subtract (m²)Subtract areas you will not paint.Number of coats (coats)Paint coverage rate (m²/L/coat)Check the paint tin or technical sheet; 10 m²/L is a planning example.Allowance (%)Optional allowance for porous surfaces, roller loss, touch-ups and colour changes.

Live result5.68 L25.8 m² paintable · 51.6 m² coated across 2 coats

Formula used

Paintable area = max(0, total wall length × wall height − openings). Coated area = paintable area × coats. Litres before allowance = coated area ÷ coverage per litre. Litres with allowance = litres before allowance × (1 + allowance percent ÷ 100).

This is the method behind the answer, so the result can be checked rather than simply trusted.

Live math canvas

Your numbers, formula and explanation together

Paint Coverage Calculator: 5.68 L. 25.8 m² paintable · 51.6 m² coated across 2 coats

Formula applied

The exact method behind this answer

CalculationTime keeps the method visible so the number can be checked instead of blindly trusted.

Paintable area = max(0, total wall length × wall height − openings). Coated area = paintable area × coats. Litres before allowance = coated area ÷ coverage per litre. Litres with allowance = litres before allowance × (1 + allowance percent ÷ 100).

Apply the formulaPaintable area = max(0, total wall length × wall height − openings). Coated area = paintable area × coats. Litres before allowance = coated area ÷ coverage per litre. Litres with allowance = litres before allowance × (1 + allowance percent ÷ 100).5.68 L25.8 m² paintable · 51.6 m² coated across 2 coats

Your live breakdown

Current inputs in the calculation

These values come from the controls above and update when the calculator changes.

Total wall length: 12 m
Wall height: 2.4 m
Doors/windows to subtract: 3 m²
Number of coats: 2 coats
Paint coverage rate: 10 m²/L/coat
Allowance: 10 %

Resulting answer

5.68 L

25.8 m² paintable · 51.6 m² coated across 2 coats

Answer: 5.68 L
Live support: 25.8 m² paintable · 51.6 m² coated across 2 coats

Assumptions used

What this answer assumes

Coverage-rate estimate only. Round to available tin sizes after checking the product and surface.

Wall dimensions are entered in metres and openings are entered in square metres.
Coverage rate is a user-entered planning value from the paint tin, supplier page or technical sheet.
The calculator treats walls as flat rectangular surfaces and does not include ceilings, trim, textured surfaces or spray loss unless you add them through the inputs.
Allowance is not a manufacturer guarantee; porous surfaces, primer, strong colour changes and application method can change real paint use.

Master’s Tip

How to use the result well

Master’s Tip: check the coverage rate on the exact product and surface. Bare plaster, dark-to-light colour changes, rough render and spraying can use more paint than a neat room-area estimate, so round purchase quantities up to available tin sizes after the arithmetic is visible.

Printable record

What belongs in the saved calculation

Save the inputs, result, formula, assumptions, page URL and date together so the calculation can be reviewed later.

Total wall length: 12 m
Wall height: 2.4 m
Doors/windows to subtract: 3 m²
Number of coats: 2 coats

What-if check

Allowance and coverage sensitivity

Paint quantity changes quickly when surface condition or product coverage changes. Use the rows below before rounding up to real tin sizes.

Allowance	Paint required	Note
0.0%	5.16 L	Planning comparison
10.0%	5.68 L	Current input
20.0%	6.19 L	Planning comparison

Coverage rate	Paint required	Change
8.0 m²/L	7.09 L	+1.42 L
10.0 m²/L	5.68 L	Current rate
12.0 m²/L	4.73 L	-0.95 L

Visual proof

Wall area minus openings

28.80 m² gross wall area − 3.00 m² openings = 25.80 m² paintable area. With 2 coats, coated area is 51.60 m².

Visual grid

This result measures part of the space you live in

Length, area, volume and material estimates are grid problems too: measure the space, account for edges and allowances, then turn the pattern into a number you can use.

Micro-timehours, minutes, shiftsHuman scaledays, weeks, projectsMacro-timemonths, years, calendars

Measured output5.68 L

Space calculations turn a real surface, room, run or volume into cells, edges and allowances that can be quoted, ordered or checked.

5.68 L25.8 m² paintable · 51.6 m² coated across 2 coats

Inputs

Total wall length: 12 m
Wall height: 2.4 m
Doors/windows to subtract: 3 m²
Number of coats: 2 coats
Paint coverage rate: 10 m²/L/coat
Allowance: 10 %

Method

Total wall area = 12 × 2.4 = 28.8 m². Subtract 3 m² of openings to get 25.8 m² paintable area. Two coats require 51.6 m² of coated area. At 10 m²/L, that is 5.16 L before allowance. With 10% allowance: 5.16 × 1.10 = 5.68 L.

Assumptions

Wall dimensions are entered in metres and openings are entered in square metres.
Coverage rate is a user-entered planning value from the paint tin, supplier page or technical sheet.
The calculator treats walls as flat rectangular surfaces and does not include ceilings, trim, textured surfaces or spray loss unless you add them through the inputs.
Allowance is not a manufacturer guarantee; porous surfaces, primer, strong colour changes and application method can change real paint use.

Notes

Use this space on the printed report for client, supplier, classroom, job-location, measurement, quote or approval notes.