Paint Calculator

Calculate exactly how much paint you need for your walls, rooms, or any surface. Get accurate estimates with cost calculations to plan your painting project.

Paint Calculator

How to Use the Paint Calculator

  1. Choose Calculation Type: Select room, individual walls, or enter known surface area
  2. Enter Dimensions: Input length, width, and height measurements in feet
  3. Specify Coats: Choose the number of paint coats (2 coats recommended for best coverage)
  4. Count Openings: Enter the number of doors and windows to subtract from surface area
  5. Select Coverage: Choose paint coverage based on surface texture and paint quality
  6. Review Results: See paint needed, cost estimates, and primer requirements

Examples and Use Cases

Common Room Sizes

12×10 ft room, 8 ft ceiling
~1 gallon for 2 coats
16×12 ft living room
~1.5 gallons for 2 coats
20×15 ft master bedroom
~2 gallons for 2 coats

Coverage Guidelines

Smooth Surfaces
400 sq ft per gallon - new drywall, smooth walls
Standard Coverage
350 sq ft per gallon - most interior walls
Rough/Textured
300 sq ft per gallon - textured, stucco, brick

Frequently Asked Questions

How accurate is this paint calculator?

Our calculator provides estimates within 10-15% accuracy for most projects. Actual paint needed may vary based on application method, surface porosity, and paint viscosity.

Should I buy exactly the calculated amount?

It's recommended to buy 10-20% extra paint for touch-ups and future maintenance. Our calculator already rounds up to the next gallon/quart for convenience.

Do I need primer for every paint job?

Primer is needed for bare surfaces, dramatic color changes, or when painting over stains. For similar colors over existing paint, primer may not be necessary.

How many coats of paint should I apply?

Two coats are recommended for best coverage and durability. Light colors over dark surfaces may need a third coat.

Professional Painting Tips

Calculate Coverage Correctly

Paint coverage varies by surface texture and paint quality. Smooth drywall needs less paint than textured walls or bare wood. One gallon typically covers 350-400 square feet with one coat on smooth surfaces. Rough surfaces like stucco or brick absorb more paint, reducing coverage to 250-300 square feet per gallon. Always buy 10-15% extra for touch-ups and waste.

Primer Requirements

New drywall, bare wood, and dark color changes require primer. Primer seals surfaces and improves paint adhesion. It often covers better than paint, requiring less topcoat. Primer coverage is similar to paint - about 350 square feet per gallon. Factor primer into your calculations when painting new construction or covering dark walls with lighter colors.

Multiple Coats

Most painting projects need two coats for solid coverage and color accuracy. Light colors over dark walls may need three coats. Multiply your square footage by the number of coats to get total coverage needed. Two coats on 400 square feet means calculating for 800 square feet total. Quality paint with better pigments may cover in fewer coats, saving time and money despite higher initial cost.

Paint Quality Matters

Premium paints cost more per gallon but spread easier, cover better, and last longer. Budget paint requires more coats and touch-ups. Calculate total project cost, not just paint cost. Paying $45 per gallon for paint that covers in two coats beats $25 paint needing three coats. Premium paints also clean easier and resist stains better, reducing maintenance.