Paint Cost Calculator
Estimate how many gallons of paint you need and the total cost to paint a room, including multiple coats and coverage rate.
How is Paint Cost Calculated?
First calculate the total paintable surface: wall area = length × height × number of walls, minus the area taken up by doors and windows. Multiply this by the number of coats for the final area. Then divide by the coverage rate (square feet per gallon) and round up to find how many gallons you need. Total cost = gallons × price per gallon.
Example
A room that is 12 ft long and 10 ft high with 4 walls has 12 × 10 × 4 = 480 sq ft of wall surface. Subtracting 30 sq ft for doors and windows gives 450 sq ft, and two coats make 900 sq ft. At 350 sq ft per gallon, you need 900 / 350 ≈ 2.6, rounded up to 3 gallons. At $25 per gallon that is $75.
Common Use Cases
- Planning a DIY painting project budget before buying paint.
- Estimating how many paint cans to buy without waste.
- Comparing costs between different paint brands with different coverage rates.
FAQs
Why do I need more paint than the wall area?
Most walls need two coats for even, lasting coverage, and you lose a little paint to waste and touch ups. Always round the gallon count up, since paint is sold in whole gallons (or cans).
Does color affect coverage?
Yes — dark or bold colors often require extra coats to achieve an opaque finish, and a primer may be needed when making a dramatic color change, which adds to the total cost.