Paint Calculator

Estimate paint for walls, ceilings, or a known area, including coats, coverage, whole cans, and optional cost.

Enter measurements below. Results update as you type, and optional prices can be added before sharing the estimate.

The calculation

Paint volume = coated area ÷ coverage

Paintable area × coats ÷ product coverage × (1 + allowance)

  • Room wall area is 2 × (length + width) × wall height.
  • Doors and windows are deducted before coats and coverage are applied.
  • The exact volume is rounded up to whole selected cans or pails for the purchase estimate.
  • Use separate estimates when walls, ceilings, primer, or trim use different products.

Quick examples

12 × 12 ft room, 8 ft walls384 sq ft of wall area before openings
Two coats at 350 sq ft/galCoated area ÷ 350 gives exact gallons
Known exterior or wall areaEnter square feet directly
Local price per 1-gallon canWhole cans × price = estimate

Examples are planning checks. Product-label coverage and whole pack sizes control the final purchase quantity.

Common questions

Understand the result before purchasing

01How much paint do I need for a room?+

Measure the room length, width, and wall height. The calculator finds the four-wall area, subtracts doors and windows, adds the ceiling when selected, multiplies by the number of coats, and divides by the product coverage rate.

02How many square feet does one gallon of paint cover?+

Coverage varies by product and surface. Many planning examples use roughly 350 to 400 square feet per gallon for one coat on a smooth surface, but the product label should control the estimate.

03Should I include two coats in a paint calculator?+

Enter the number of coats recommended for the product, color change, and surface. The calculator multiplies the net paintable area by the selected coat count before estimating volume.

04Should doors and windows be subtracted?+

Large doors and windows can be deducted when they will not be painted. Small openings may be left in the area as a practical allowance for cutting in, touch-ups, and measurement variation.

05Can this calculate ceiling paint?+

Yes. Room mode includes an optional ceiling area equal to room length multiplied by room width. Use separate calculations when walls and ceilings use different products, colors, coverage rates, or prices.

06Can I calculate paint cost?+

Yes. Choose a container size and enter the local price per container. The calculator rounds the required volume up to whole containers and multiplies by the entered price.

07Can I share my paint estimate?+

Yes. Use Copy estimate link in the result panel. The link stores the current room, coverage, coat, waste, container, and price inputs in the URL so the estimate can be reopened.