Solve backwards
How much siding will my exterior paint cover?
- 10 galThe example worked below
- Exterior Paint CalculatorEvery figure is its own
You have
How much exterior paint?
That is 10 gal(37.9 L). Worked by the Exterior Paint Calculator at the settings below.
The settings it uses
- Number of Coats
- 2
What it will do
1,500 sq ft of siding
139 m²
One one-storey house. Enough for the walls of a one-storey house about 47 × 47 ft with 8 ft walls.
Or several. About 1 one-storey house of the size the Exterior Paint Calculator opens on: the walls of a one-storey house about 34 × 34 ft with 8 ft walls.
Check it forwards
- Exterior Wall Area
- 1,500 sq ft
- It asks for
- 10 gal
- You have
- 10 gal
The Exterior Paint Calculator asks for 10 gal at that size, and 10.5 gal one step larger.
If you had more, or less
Around your amount
Each worked by the Exterior Paint Calculator at the same settings.
Half
5 gal
750 sq ft
the walls of a one-storey house about 23.4 × 23.4 ft with 8 ft walls
Yours
10 gal
1,500 sq ft
the walls of a one-storey house about 47 × 47 ft with 8 ft walls
Half as much again
15 gal
2,250 sq ft
the walls of a one-storey house about 70 × 70 ft with 8 ft walls
Double
20 gal
3,000 sq ft
the walls of a one-storey house about 94 × 94 ft with 8 ft walls
Common amounts
What each amount of exterior paint covers
The sizes it is usually sold in, each worked by the Exterior Paint Calculator at the settings above.
| You have | It covers | As one one-storey house | Average one-storey houses |
|---|---|---|---|
| 5 gal(18.9 L) | 750 sq ft(69.7 m²) | the walls of a one-storey house about 23.4 × 23.4 ft with 8 ft walls | under 1 |
| 10 gal(37.9 L) | 1,500 sq ft(139 m²) | the walls of a one-storey house about 47 × 47 ft with 8 ft walls | 1 |
| 15 gal(56.8 L) | 2,250 sq ft(209 m²) | the walls of a one-storey house about 70 × 70 ft with 8 ft walls | 2 |
| 20 gal(75.7 L) | 3,000 sq ft(279 m²) | the walls of a one-storey house about 94 × 94 ft with 8 ft walls | 2 |
The rate is fixed, and set in the middle
The exterior calculator applies 300 square feet per US gallon per coat, about 28 m² per 3.8 litres, from the 250 to 350 square feet its source quotes for siding. It has no field for the rate on your tin, so on rough or chalky siding at the 250 end the same paint covers about a sixth less wall than shown.
Small windows stay in the area on purpose
The calculator's own guidance is to leave small windows and doors in the wall area as a buffer for the trim work around them, and to take out only the large openings such as garage doors. So the house here is the walls as measured, and a heavily glazed elevation leaves more paint over than the answer suggests.
Two coats, and no primer counted
Two coats is standard for new siding or a colour change, and one may do for a same-colour refresh over sound paint — which doubles the siding here. Bare wood, masonry or a strong colour change may also want a primer coat, and the calculator counts no primer, so that comes from a separate tin.
How the answer is worked
Nothing here is a second formula. The Exterior Paint Calculator runs forwards — a size in, a quantity out — and this page grows its own starting one-storey house 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.
Exterior Paint Calculator
runs it forwardsEstimate how many gallons or litres of exterior paint you need, accounting for rougher-surface coverage rates.
Work out what to buy insteadSolve backwards
Other things you might already have
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How much fence will my stain cover?
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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 siding does 10 gal of exterior paint cover?
- At the Exterior Paint Calculator's own settings, 1,500 sq ft (139 m²) — the walls of a one-storey house about 47 × 47 ft with 8 ft walls. That is about 1 one-storey house of the size the calculator opens on: the walls of a one-storey house about 34 × 34 ft with 8 ft walls. Every figure follows the settings, which you can change in the calculator.
- How much siding does 40 L of exterior paint cover?
- At the Exterior Paint Calculator's own settings, 146 m² (1,575 sq ft) — the walls of a one-storey house about 15.2 × 15.2 m with 2.4 m walls. That is about 1 one-storey house of the size the calculator opens on: the walls of a one-storey house about 10.4 × 10.4 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 exterior paint cover?
- About 250 to 350 square feet per US gallon per coat on siding, roughly 23 to 33 m² per 3.8 litres, which is less than interior paint's 350 to 400 because siding is textured and porous. The calculator uses 300 square feet per gallon; the rate on your tin is the one to trust.
- How much exterior paint does a small house need?
- Measure each wall's height times its width and add them, taking out only large openings such as garage doors. Two coats over that area at 300 square feet per gallon is the calculator's figure, rounded up to the next half gallon — the table above reads the same relation the other way.
- Is the gallon here a US gallon or an imperial one?
- Always the US gallon of 3.785 litres. The calculator works in US gallons and square feet and restates the answer in litres for a metric reader, so a litre figure here is a converted US gallon, still carrying its half-gallon step, rather than a metric tin size.