Home & projects
Estimate interior or exterior paint quantities from measured surfaces, openings, coat count, product coverage, and a practical waste allowance.
Calculator set
Open a calculator for an immediate estimate, then use its method notes, examples, limits, and sources to understand the result.
Understand, then calculate
Paint quantity is driven by net surface area, number of coats, product coverage, surface condition, and application loss. A good estimate keeps each assumption visible.
Measure first, subtract openings consistently, and use the coverage printed on the product you intend to buy. Separate primers and finish coats when their coverage differs.
Identify the decision first, then open the calculator that answers it.
Understand the recurring inputs and results instead of reading only the final number.
Choose with context
Use these distinctions to move through the Painting projects tools without comparing unrelated results.
Choose the interior calculator for rooms and individual walls.
Choose the exterior calculator for façades, gables, doors, and windows.
Use the coverage printed on the actual product before buying.
Results are planning estimates. Confirm site dimensions, product specifications, and installation waste before purchasing.
Common questions
These answers explain how to use the estimates and where their limits begin.
Subtract large openings consistently. For small openings, the saved paint may be offset by extra cutting-in work and surface loss.
Texture, porosity, weathered surfaces, overspray, and complex trim can increase actual use.