Paint Cost Calculator
Budget-first paint tool: start from paintable area, coats, coverage and your price per gallon. For wall dimensions that produce the area, use the Paint Calculator first.
Enter your measurements to see what to buy.
How to calculate it
Budget-first paint tool: start from paintable area, coats, coverage and your price per gallon. For wall dimensions that produce the area, use the Paint Calculator first.
Source: Gallons = paintable area × coats ÷ coverage per gallon. Standard coverage ~350 ft²/gal; cost = gallons × price per gallon.
400 ft² of wall, 2 coats, 350 ft²/gal, $45/gal: 400 × 2 ÷ 350 = 2.3 → 3 gallons × $45 = $135 estimated material cost.
Want the full step-by-step walkthrough? Read our How to Estimate Paint for a Room.
Purchasing & waste guidance
- One gallon covers about 350–400 ft² of smooth, primed wall — check your can.
- Buy all paint at once and mix gallons together for consistent color.
- Budget for primer on new drywall or dramatic color changes.
- Costs are estimates — paint prices vary by brand, line and finish.
Assumptions & what’s included
- Paintable area is the wall surface to cover (minus openings you deduct yourself).
- Coverage defaults to 350 ft²/gal — adjust to match your paint can.
- Gallons are rounded up for touch-up leftover. Cost is an estimate and may vary.
Frequently asked questions
How much will it cost to paint a room?
A 12×12 room with 8 ft walls needs about 2 gallons for two coats. At $45 per gallon that is roughly $90 in paint. Enter your area, coverage and price for an exact estimate.
How many gallons of paint do I need for 400 square feet?
400 ft² with two coats at 350 ft²/gal needs about 2.3 gallons — round up to 3 gallons so you have leftover for touch-ups.
Are the cost estimates accurate?
They are estimates based on the price per gallon you enter. Paint prices vary by brand, finish and retailer, so enter your actual quoted price for the most accurate total.
Related guides
Step-by-step project guides that use this calculator.