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Professional

Verified calculator with a transparent formula

Professional

Paint Coverage Calculator.

Estimates the amount of paint needed to cover a given wall area, accounting for the number of coats and paint efficiency.

Results update live as you type.
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Your inputs

How it works

  1. 1

    Enter the total wall area to be painted in square feet.

  2. 2

    Specify the number of coats you plan to apply.

  3. 3

    Enter the paint coverage per gallon (usually listed on the can).

  4. 4

    The calculator divides the total area by the coverage to give gallons needed.

wall_area * coats / coverage_per_gallon

Frequently asked questions

What is typical paint coverage per gallon?

Most paints cover 250-400 square feet per gallon, depending on surface texture and porosity.

Should I account for waste?

Yes, it's wise to add 10-15% extra for spills, touch-ups, and uneven surfaces.

How do I calculate for multiple rooms?

Add the wall areas of all rooms together before entering the total area.

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Results

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Paint Needed

0gallons

Cans to Buy (1 gal)0cans
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Estimate for general guidance only — verify important decisions with an appropriate professional.

How it works

Estimates the amount of paint needed to cover a given wall area, accounting for the number of coats and paint efficiency.

  1. Enter the total wall area to be painted in square feet.
  2. Specify the number of coats you plan to apply.
  3. Enter the paint coverage per gallon (usually listed on the can).
  4. The calculator divides the total area by the coverage to give gallons needed.

Formulas

The math behind this calculator, written out so you can verify the result.

Paint Needed

Gallons = (Wall Area × Number of Coats) / Coverage per Gallon

Multiply the wall area by the number of coats to get total area to cover, then divide by the paint's coverage rate.

Example:

Input: Wall Area = 400 sq ft, Coats = 2, Coverage = 350 sq ft/gal

Calculation: 400 × 2 / 350

Result: ≈ 2.29 gallons

Real-world use cases

Where this calculation shows up in everyday life.

Home DIY Painting

Plan how much paint to buy for a bedroom or living room without overbuying.

Example: A 12x12 room with 8-ft ceilings has about 384 sq ft of wall area.

Contractor Estimates

Quickly estimate paint quantities for multiple rooms or entire houses.

Example: Estimate for a 2,000 sq ft house with 2 coats.

Budgeting

Calculate paint cost by multiplying gallons needed by price per gallon.

Example: If paint costs $30/gal, 3 gallons cost $90.

Tips and common mistakes

Tips

  • Always round up to the nearest gallon when buying paint.
  • Test coverage on a small area if the surface is rough or highly absorbent.
  • Use a primer for new drywall or stained surfaces to reduce paint absorption.
  • Consider buying paint in 5-gallon buckets for large projects to save money.

Common Mistakes to Avoid

  • Forgetting to multiply by the number of coats.
  • Using the ceiling area instead of wall area.
  • Not accounting for doors and windows – subtract their areas from the total wall area.

Assumptions and limitations

  • Use the stated inputs and units.
  • Results are estimates for planning and education.
  • Check measurements and source data before making an important decision.