Paint calculators
Work out how many gallons of paint and primer a room needs from its walls, coats, and the coverage on your can, then turn that quantity into a material budget.
Paint calculators
Paint Calculator
Estimate gallons of wall paint from room size, coats, coverage, and allowance.
PaintPaint Cost Calculator
Turn your paint quantity into a budget using your own price and supplies.
PaintCeiling Paint Calculator
Estimate ceiling paint from floor dimensions, coats, coverage, and allowance.
PaintPrimer Calculator
Estimate gallons of primer for walls using your primer label coverage.
PaintPaint workflow
Work through it in order.
Each step feeds the next, so the measurement you trust becomes the quantity you buy.
- Step 01 Measure the walls Wall Area Calculator: Subtract doors and windows. Open calculator
- Step 02 Prime if needed Primer Calculator: New drywall, patches, stains, big color changes. Open calculator
- Step 03 Estimate the topcoat Paint Calculator: Gallons from coats and coverage. Open calculator
- Step 04 Price the job Paint Cost Calculator: Your price per gallon plus supplies. Open calculator
Paint guides
Short, practical answers to go with the calculators.
How much paint do I need?
Understand wall area, coats, openings, coverage, and the allowance that changes the answer.
How much paint for a 12x12 room?
A worked example with the arithmetic shown, plus how ceiling height, coats, and coverage change it.
How much does a gallon of paint cover?
What the coverage on the can means, why real walls get less, and how coats and texture change the number.
One coat vs two coats of paint
When a single coat can be enough, why most projects plan two, and how much paint each choice really takes.
How to measure walls for paint
Use perimeter, height, and measured openings to get a cleaner paintable surface area.
How much primer do I need?
When primer is part of the job, why its coverage differs from paint, and how to estimate it.
Common questions
How much paint do I need for a room?
Find the net wall area, multiply by the number of coats, and divide by the coverage on your can. The paint calculator does this and rounds up to whole gallons.
Should I estimate walls and ceiling together?
Separately. Ceilings usually use a different product and the area is the floor area, so the ceiling paint calculator handles it on its own.
Where does the coverage number come from?
From your paint or primer label. Our defaults are editable planning examples, not a promise for every product or surface.