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Paint Calculator

Estimate paint for one room or a whole house. Measure by room dimensions or direct wall area, subtract doors and windows, include ceilings, and see gallons, quarts, and cost instantly.

sq ft
$

Rooms

Add each room, switch between dimensions or direct wall area, and include ceilings if needed.

ft
ft
ft

Subtracts 20 sq ft each.

Subtracts 15 sq ft each.

Total area

0.0 sq ft

Paintable area

0.0 sq ft

Openings removed

20.0 sq ft

Room

Room 1

Paint Estimate

Total wall area

0.0 sq ft

Paintable area

0.0 sq ft

Gallons needed

0.00 gal

Quarts needed

0.0 qt

Estimated paint cost

$0.00

Assumptions

2 coats at 350 sq ft per gallon.

Editorial noteMaintained by EveryCalc - Reviewed June 2026

EveryCalc calculators are designed for fast, practical estimates with transparent inputs and no required account. We use plain formulas, visible assumptions, and related tools so visitors can check the result from more than one angle.

Results are informational only. For financial, tax, legal, medical, construction, or other high-impact decisions, verify the output against primary sources or a qualified professional.

Learn more about our review process on the EveryCalc methodology page.

How this calculator works

What this page estimates

This Paint Calculator is built to give a quick, browser-based estimate for paint. Estimate paint for one room or a whole house. Measure by room dimensions or direct wall area, subtract doors and windows, include ceilings, and see gallons, quarts, and cost instantly. The inputs stay on the page during normal use, and the result should be treated as an estimate for planning, comparison, or education rather than professional advice.

Calculation approach

The calculator applies the standard relationship implied by the inputs, then formats the answer so it can be checked and reused. For home & construction tools, the most important step is using consistent units, rates, time periods, and assumptions before comparing the result with another calculator or outside quote.

Example workflow

For example, start with a realistic value you already know, change one input at a time, and watch how the answer moves. That makes it easier to tell whether the result is being driven by the main amount, the rate, the time period, or a unit conversion.

Practical checks

  • Use current, real-world numbers when the result affects money, health, tax, or legal decisions.
  • Run a low, base, and high case when the inputs are estimates.
  • Check the related calculators below when the next decision depends on a different assumption.

How to interpret the paint result

Best use

Use the result to size a project, compare materials, estimate a reserve, or decide whether a contractor quote is in the expected range.

Cross-check

Compare the estimate with local code, site measurements, supplier pricing, utility bills, permit rules, and contractor scopes before buying materials.

Watch for

Project estimates are sensitive to waste, labor, access, climate, soil, and existing conditions. Add contingency when the job cannot be measured cleanly.

This page belongs to the Home & Construction calculator library, so the answer should be read in the context of the decision you are modeling rather than as a universal rule.

Before relying on this paint estimate

Most calculator mistakes come from the inputs, not the arithmetic. Use this short audit before you reuse the answer in a spreadsheet, quote, application, or important conversation.

Measure the actual site

Square footage, slope, access, waste, existing conditions, and local material availability can change a project estimate quickly.

Add contingency

Cuts, breakage, delivery issues, weather, permits, and hidden repairs often make the real budget higher than a clean calculation.

Compare with local pricing

Supplier quotes, contractor scopes, code requirements, and permit fees should control the final budget.

Rerun this page after new measurements, contractor quotes, material price changes, permit comments, or scope changes.

How to Use

  1. Add one or more rooms and choose whether to calculate from dimensions or direct wall area.
  2. Enter room measurements or total square footage, then adjust doors, windows, and the ceiling option.
  3. Set your number of coats, coverage per gallon, and paint price per gallon.
  4. Review total wall area, paintable area, gallons needed, quarts needed, and your estimated cost.

Frequently Asked Questions

How many square feet does a gallon of paint cover?

A typical gallon of interior paint covers about 350 to 400 square feet per coat, depending on the paint type, surface texture, and how much the wall absorbs.

Should I include doors and windows in my paint estimate?

Yes. Subtracting doors and windows gives a more accurate estimate, especially across multiple rooms. A common rule of thumb is about 20 square feet per door and 15 square feet per window.

Do I need two coats of paint?

Usually yes. Two coats are common for color changes, new drywall, patchy surfaces, or when you want an even finish. One coat may be enough for touch-ups or when using high-hide paint over a similar color.

How do I estimate ceiling paint?

Ceiling area is usually length × width for each room. If you plan to paint the ceiling, include that area in addition to the wall area.

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