Paint Calculator

Estimate paint gallons from measured wall area, coat count and label coverage, with whole-gallon rounding and a two-coat worked example. Calculate it clearly with Figur.

Calculate paint gallons from area, coats and coverage

Paint needed = wall area in square feet × number of coats ÷ coverage in square feet per gallon per coat. The tool shows the unrounded requirement and rounds up to whole gallons for buying. Measure the paintable area yourself and deduct openings before entering it; this tool does not calculate room walls. Use the coverage on your chosen paint's label, not a guaranteed universal rate.

Method and assumptions

Exact gallons = wall area × coats ÷ coverage. Gallons to buy = exact gallons rounded up to the next whole gallon.

  • The same coverage applies to every coat and every surface entered; coats are a whole number of at least one.
  • There is no separate waste percentage. Whole-gallon rounding is not a surface-specific waste allowance.
  • Primer, trim, ceilings and doors are excluded unless you include their paintable area; different products should be estimated separately.
  • Texture, porosity, color changes and application technique can change coverage. Use a positive label coverage.

Planning takeoff, not a binding bid, structural design or engineering advice. Confirm field measurements, product coverage, installation requirements and supplier quantities before buying.

Sources and references

The result uses your inputs and the tool's documented assumptions; it does not fetch current prices, rates or products.

Worked example

Paint 400 sq ft with 2 coats using paint labeled for 300 sq ft per gallon per coat.

400 × 2 ÷ 300 = 2.67 gallons before rounding. Buy 3 gallons under the tool's whole-gallon assumption.

Frequently asked questions

Does the calculator measure walls or subtract windows?

No. Enter the net area you plan to paint. For a room, measure wall lengths and height, then subtract openings as appropriate.

Does it include primer and waste?

Not separately. Calculate primer using its own coverage and add any project-specific reserve yourself; the purchase result only rounds up to whole gallons.

Why is the buying amount larger than the exact amount?

Paint is estimated in whole gallons here. A requirement of 2.67 gallons becomes 3 gallons; it does not optimize quart or multi-gallon containers.

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