Calculating your paint needed is straightforward once you know the Paint formula and what each input means. This guide explains the method in plain language, walks through a manual calculation, and gives worked examples you can follow — then you can do it instantly with the Paint Calculator.
What is Paint?
The Paint calculation tells you your paint needed from a few simple inputs. The figure you are solving for here is the paint needed.
The Paint formula
This calculation combines several inputs through a multi-step method rather than a single one-line formula. Enter the values below and the calculator resolves each step in order. The inputs it needs are:
- Total wall area — a value measured in sq ft. Example: 400 sq ft.
- Number of coats — a number. Example: 2.
- Coverage per litre — a value measured in sq ft/L. Example: 110 sq ft/L.
How to calculate it step by step
- Write down the total wall area (for example, 400 sq ft).
- Write down the number of coats (for example, 2).
- Write down the coverage per litre (for example, 110 sq ft/L).
- Apply the formula above to get your paint needed.
- Double-check the result with the Paint Calculator.
Worked examples
Example 1
| Input / Output | Value |
|---|---|
| Total wall area | 400 sq ft |
| Number of coats | 2 |
| Coverage per litre | 110 sq ft/L |
| Paint needed | 8 |
| Exact litres | 7.27 |
With total wall area of 400 sq ft, number of coats of 2 and coverage per litre of 110 sq ft/L, the paint needed works out to 8.
Example 2
With total wall area of 800 sq ft, number of coats of 2 and coverage per litre of 110 sq ft/L, the paint needed works out to 15.
| Result | Value |
|---|---|
| Paint needed | 15 |
| Exact litres | 14.55 |
Example 3
With total wall area of 200 sq ft, number of coats of 2 and coverage per litre of 110 sq ft/L, the paint needed works out to 4.
| Result | Value |
|---|---|
| Paint needed | 4 |
| Exact litres | 3.64 |
Tips for an accurate result
- Keep your units consistent — mixing, say, months with years or grams with kilograms is the most common source of error.
- Round only at the very end. Rounding inputs early can shift the final answer noticeably.
- Re-run the numbers whenever an input changes, rather than estimating from an old result.
Prefer not to do the maths by hand? — the Paint Calculator does it instantly, for free, with the formula and a worked example built in.
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