Free Painting Calculators
Work out how much paint to buy for walls, ceilings or a house exterior. Use our free painting calculators to estimate paint coverage, quantities and project costs with clear formulas and practical examples.
Browse painting calculatorsPainting Calculators
Paint Calculator
Calculate how much paint you need for your project, including wall area, number of coats, primer, paint coverage and estimated cost.
Use the calculator →Paint Coverage Calculator
Estimate how much surface area your paint will cover and plan your painting project using paint quantity and coverage rates.
Use the calculator →Cost to Paint Interior of House Calculator
Estimate the cost of painting your home’s interior based on room sizes, paint requirements, labor and other project expenses.
Calculate Painting Cost →Quick Paint Facts
Paint needed in gallons = surface area × number of coats ÷ coverage per gallon.
One gallon of paint typically covers about 350 to 400 square feet per coat on a smooth surface. Actual coverage varies by product and surface condition.
Two coats are common for many painting projects. Bare surfaces, repairs and major color changes may require primer or additional coats.
How to Use the Painting Calculators
- Measure the surface. Measure the wall length, width and height, and account for doors, windows and other areas that will not be painted.
- Estimate paint coverage. Use the Paint Coverage Calculator to estimate the area a given amount of paint can cover.
- Calculate paint quantity. Open the Paint Calculator to estimate the amount of paint required for your area and number of coats.
- Account for surface conditions. Check the paint manufacturer’s coverage rate and allow for rough, porous or previously unpainted surfaces where necessary.
- Plan your purchase. Consider primer, additional coats and a small amount of extra paint for touch-ups. Follow the manufacturer’s instructions.
More Project Calculators
Drywall Calculators
Estimate drywall sheets, joint compound, materials and installation costs.
Browse drywall →Roofing Calculators
Calculate roof pitch, roof area, rafters and estimated replacement costs.
Browse roofing →Flooring Calculators
Estimate square footage and material quantities for tile, hardwood, carpet and other flooring projects.
Browse flooring →Concrete Calculators
Work out concrete volume, bags, slabs, footings and cost for driveways, patios and foundations.
Browse concrete →Frequently Asked Questions
Are the painting calculators free?
Yes. The Calctoolz painting calculators are available free to use without an account.
How many square feet does a gallon of paint cover?
A gallon typically covers about 350 to 400 square feet per coat on a smooth surface. Check the label on your paint can for the manufacturer’s stated coverage.
How many coats of paint do I need?
Two coats are common for many walls. The number required depends on the existing color, the new color, surface condition, paint type and whether primer is needed.
What is the difference between a paint calculator and a paint coverage calculator?
A paint calculator estimates how much paint is needed for a project. A paint coverage calculator estimates the surface area that a given quantity of paint can cover. Both can help you plan material purchases.
Should I subtract doors and windows when calculating paint?
Yes. Subtract large doors, windows and other unpainted areas for a more accurate estimate. You should also account for surface texture, absorption and the number of coats.
These calculators provide planning estimates only. Actual paint requirements vary according to the product, application method and surface condition. Always follow the manufacturer’s instructions. Read our Disclaimer.