Interior Door Paint Calculator
Estimate paint for interior doors by size, sides, and coats, with quarter-gallon rounding up.
Find how much paint you need for one or more interior doors. It counts both faces of each door and rounds up to the next quarter gallon.
Your details
Count every door you plan to paint.
Measure the door slab width.
Measure the door slab height.
Most interior doors have 2 paintable faces.
How many coats you plan to apply.
Result
Square feet of door surface, not multiplied by coats.
- Gallons to buyRounded up to the next quarter gallon.
- 0.25
- Total coverageSquare feet covered across all coats.
- 71.1
About this tool
How to Estimate Paint for Interior DoorsLearn the simple door-paint math: area, sides, coats, and why the calculator rounds up to the nearest quarter gallon.
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Door Painting Measure & Shop SheetMeasure every door before you buy paint so you can shop with the right amount in hand.
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Interior Door Paint Calculator infographicThe key numbers as one image — free to save, share, or embed on your own site with credit.
How this is calculated
Area is calculated from door width × door height × number of doors × sides painted. That gives total door surface in square feet. Paint needed is based on coats × total area ÷ coverage per gallon. A standard interior latex coverage rate of 350 sq ft per gallon is used, which is a common label value. The gallons-to-buy result is rounded up to the next 0.25 gallon, since paint is sold in quarts. This tool assumes a flat door surface and does not subtract windows, panels, or trim.
Common questions
- Why does it count both sides of the door?
- Because a painted door has two faces. If you only count one side, you understate the paint needed by half.
- Why round up to a quarter gallon?
- Paint is commonly sold in quarts, so quarter-gallon rounding matches what you can actually buy.
- What coverage rate does this use?
- It uses 350 square feet per gallon, a standard interior latex coverage figure found on many paint labels.
Take it further with AI
Copy this into ChatGPT or Claude with your own numbers filled in. It hands over the figures this calculator worked out, so the answer is built on real arithmetic instead of a guess.
I used the Interior Door Paint Calculator at https://www.bfcbrilliance.com/tools/interior-door-paint-calculator.
What I entered:
- Number of doors (doors): ___
- Door width (in): ___
- Door height (in): ___
- Sides painted (faces): ___
- Coats (coats): ___
What it calculated:
- Total area: ___
- Gallons to buy: ___
- Total coverage: ___
Use those figures as given — they are already worked out, so please don't recalculate or estimate your own. Help me turn them into a plan: what to buy or do, in what order, roughly what it should cost, and the mistakes people most often make with this job.
Where the job touches structure, gas, or electrics, tell me to check local building code and whether a permit or a licensed trade is required.Last updated
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Part of a bigger job
How to Estimate a Painting JobMeasure once, buy once. Which calculator to use for walls, ceilings, doors, cabinets and outside — and the three places people always come up short.
Walks through all 8 painting & decorating tools in order.