Solve backwards
How much wall will my paint cover?
- 24 galThe example worked below
- Paint CalculatorEvery figure is its own
You have
How much wall paint?
That is 24 gal(90.8 L). Worked by the Paint Calculator at the settings below.
The settings it uses
- Wall Height
- 8 ft
- Number of Doors
- 1
- Number of Windows
- 2
- Area of One Door
- 21 sq ft
- Area of One Window
- 15.1 sq ft
- Number of Coats
- 2
- Paint Coverage
- 400 ft²/gal
What it will do
About 4,800 sq ft of wall
446 m² — the Paint Calculator's own room, times how many of them the amount covers
One room. More than one room — see the count of average ones below.
Or several. About 14 rooms of the size the Paint Calculator opens on: the walls of a room 13 × 11.5 ft with 8 ft walls.
If you had more, or less
Around your amount
Each worked by the Paint Calculator at the same settings.
Half
12 gal
2,400 sq ft
the walls of a room 81 × 72 ft with 8 ft walls
Yours
24 gal
about 4,800 sq ft
more than one room
Half as much again
36 gal
about 7,200 sq ft
more than one room
Double
48 gal
about 9,600 sq ft
more than one room
Common amounts
What each amount of wall paint covers
The sizes it is usually sold in, each worked by the Paint Calculator at the settings above.
| You have | It covers | As one room | Average rooms |
|---|---|---|---|
| 1 gal(3.8 L) | 200 sq ft(18.6 m²) | the walls of a room 8.3 × 7.4 ft with 8 ft walls | under 1 |
| 2 gal(7.6 L) | 400 sq ft(37.2 m²) | the walls of a room 15 × 13.2 ft with 8 ft walls | 1 |
| 5 gal(18.9 L) | 1,000 sq ft(92.9 m²) | the walls of a room 35 × 31 ft with 8 ft walls | 2 |
| 10 gal(37.9 L) | 2,000 sq ft(186 m²) | the walls of a room 68 × 60 ft with 8 ft walls | 5 |
| 24 gal(90.8 L) | about 4,800 sq ft(446 m²) | more than one room | 14 |
The rate on the tin is for a wall that is already sealed
North American wall paints are commonly rated at 350 to 400 square feet per US gallon, about 8.6 to 9.8 square metres per litre, and many UK and European emulsions state up to 13 to 17 square metres per litre. Those figures are for a smooth wall that has been painted before. New plaster, bare drywall and heavy texture take more on the first coat, so a room being painted for the first time comes out smaller than the answer here. Put your tin's own rate into the calculator and the room follows it.
Every coat is the whole wall again
Two coats is the default because one is rarely enough for an even, opaque finish, least of all over a different colour. That halves the answer: the paint that finishes one room at two coats would put a single coat on two. A dark-to-light change or unprimed drywall can need a third, and the room shrinks again by the same proportion.
The room keeps the calculator's shape
The largest room is grown from the calculator's own default room, so it keeps that room's proportions and its wall height, and it still loses one door and two windows at the standard allowances of about 21 and 15 square feet (1.95 and 1.4 m²). Several small rooms use the same paint differently from one large one, because each brings its own door and windows — which is why the count of average rooms sits beside the one big room rather than instead of it.
How the answer is worked
Nothing here is a second formula. The Paint Calculator runs forwards — a size in, a quantity out — and this page grows its own starting room in proportion until the quantity it asks for is what you have. Where it rounds up to whole containers, the answer is the largest size before the next one would be needed.
Where the calculator adds an allowance for cuts or breakage when you order, the same allowance comes off here, because it is the same calculator: a stack you already own finishes less than its face value. Where it adds none, neither does this page — the settings beside the answer say which.
Paint Calculator
runs it forwardsEstimate how much paint you need for a room based on its dimensions, doors, windows, and number of coats.
Work out what to buy insteadSolve backwards
Other things you might already have
How many ceilings will my paint cover?
Ceiling paint, worked by the Ceiling Paint Calculator.
How much wall will my primer cover?
Primer, worked by the Paint Primer Calculator.
How much siding will my exterior paint cover?
Exterior paint, worked by the Exterior Paint Calculator.
How big a deck will my stain cover?
Deck stain, worked by the Deck Stain Calculator.
How much fence will my stain cover?
Fence stain, worked by the Wood Fence Stain Calculator.
How big a patio will my paver sealer cover?
Paver sealer, worked by the Paver Sealer Calculator.
Solve backwards
Start from what is already in the yard
Paint, sheets, rolls, bags and pieces, each read the other way by the calculator that orders it.
The calculator's own figures
Nothing is estimated twice: the page runs the same calculator you would order with.
The largest size that fits
Where a calculator rounds up to whole containers, the answer stops before the next one.
Both unit systems
Gallons and litres, square feet and square metres, side by side.
Frequently asked questions
- How much wall does 24 gal of wall paint cover?
- At the Paint Calculator's own settings, about 4,800 sq ft (446 m²). That is about 14 rooms of the size the calculator opens on: the walls of a room 13 × 11.5 ft with 8 ft walls. Every figure follows the settings, which you can change in the calculator.
- How much wall does 20 L of wall paint cover?
- At the Paint Calculator's own settings, 100 m² (1,076 sq ft) — the walls of a room 11.6 × 10.2 m with 2.4 m walls. That is about 3 rooms of the size the calculator opens on: the walls of a room 4 × 3.5 m with 2.4 m walls. Every figure follows the settings, which you can change in the calculator.
- How many square feet does a gallon of wall paint cover?
- Most North American wall paints state 350 to 400 square feet per US gallon for one coat, about 8.6 to 9.8 square metres per litre. At two coats that is half the wall — roughly 175 to 200 square feet per gallon, 4.3 to 4.9 m² per litre — before doors and windows are taken off. The tin's own figure is the one to trust.
- Why does my room need more paint than the tin says?
- Because the stated rate assumes a sealed, previously painted surface and an even film. New plaster, bare board, patched areas and rough texture absorb more on the first coat, and paint left in the tray and the roller sleeve never reaches the wall. The paint calculator counts the bare requirement, so keep a little back for touch-ups.
- Should I count doors and windows when working out how far my paint goes?
- Yes — they are wall you are not painting. The answer here takes off one door and two windows per room at the usual allowances, about 21 square feet (1.95 m²) for a door and 15 (1.4 m²) for a window. A room with a patio door or a wall of glass leaves more paint over for the rest of the house.