Paint calculator
Plan finish paint for your room's walls. Enter dimensions, openings, coats, and product coverage, then save your quantities and paint details in a purchase PDF.
Start with your measurements
Size up your project
Example values are filled in. Replace them with your project measurements.
Walls only. Each door deducts 21 sq ft and each window 15 sq ft; compare these assumptions with your openings.
Before you order
- Confirm paint coverage, finish and coats for the surface.
- Ask whether primer is needed and calculate it from its own coverage.
Quantities to confirm
Paint purchase sheet
- Interior finish paint2 coat(s) over net wall area at 350 sq ft/gal; round up to whole gallons.
- 2gal
- Primer, if neededConfirm whether primer is required, its coat count and product coverage.
- Confirmgal
What this estimate assumes
- Walls only. Door allowance: 21 sq ft each; window allowance: 15 sq ft each. Net wall area: 312 sq ft.
- Coverage is the entered 350 sq ft/gal/coat. Whole gallons do not specify can size. Primer need, coats and coverage are unconfirmed.
Name your project & add notes Optional
Includes your quantities, assumptions and space to record the supplier, confirmed quantity, quote and delivery. No account required.
How to check this list before buyingWhat the estimate includes
This model covers two pairs of rectangular walls. Each door deducts 21 sq ft and each window 15 sq ft; these are planning dimensions. Ceilings, trim, and different paint colors need separate estimates.
Turn gallons into a purchase
Check your paint's coverage and available container sizes. Record the product, color, sheen, and room on the sheet. Primer stays unquantified until you confirm whether it is required, how many coats are needed, and its own coverage.
Review how to read your material shopping list before downloading the Letter or A4 PDF.
Frequently asked questions
How many gallons of paint do I need for a 12x12 room?
The initial 12x12 ft example has 8 ft walls, two doors, two windows, and two coats. Using the stated opening deductions gives 312 sq ft of net wall area. At the initial 350 sq ft per gallon per coat, 312 × 2 / 350 is about 1.78 gallons, rounded up to 2 whole gallons of finish paint. Primer is separate and its quantity is unknown.
How much does one gallon of paint cover?
Use the coverage stated for your chosen paint and surface. The calculator starts at a planning value of 350 sq ft per gallon per coat; update it to match the product. Whole-gallon rounding does not select a can size or determine primer needs.