Quick answer
Estimate room paint for four walls using room dimensions, ceiling height, openings, coats and product coverage. Use the working RenoMetric calculator below for the actual estimate, then use this page to check assumptions, package rounding and project-specific considerations.
Open the working Paint calculator
Formula
Worked planning example
A 12 × 10 ft room with 8 ft walls has 352 ft² of gross wall area before subtracting doors and windows.
Common uses
- Bedrooms
- Home offices
- Nurseries
- Apartment turnovers
How to get a better estimate
Measure the actual project rather than relying on listing dimensions. For irregular spaces, split the surface into simple measurable sections and add the results. Use the exact product label for package coverage, yield, density or square-foot coverage whenever it is available.
Keep waste and package rounding as separate steps. Waste covers cuts, breakage, pattern matching and unavoidable offcuts. Package rounding reflects the fact that many materials are sold only in complete bags, boxes, bundles or cans.
Before you buy: this page is a planning guide, not a contractor quotation or structural design. Verify final quantities with the product manufacturer, supplier or installer when project conditions could materially change the result.
Room Paint Calculator FAQ
Does this include the ceiling?
Not unless you intentionally add ceiling area. Ceiling paint is best estimated separately because product and finish may differ.
Should closets be included?
Include them if they will be painted with the same product. Measure them separately for clearer planning.
Why does the result round up?
Paint is sold in fixed container sizes, and a small reserve is useful for cutting in and touch-ups.