Paint Calculator — Free Wall Area & Gallons Estimator

Free paint calculator. Add rooms with dimensions, doors, windows to estimate wall area, gallons needed, and cost. 100% client-side. 100% serverless.

🔒 100% Private
Completely Free
🌐 Runs in Browser
📦 Export Ready

Paint Calculator — Free Wall Area & Gallons Estimator

Tool Workspace

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  1. Add Rooms — Enter length, width, height, doors, windows.
  2. Settings — Coats, coverage per gallon, price.
  3. Calculate — See wall area, paintable area, gallons, cost.

Paint Calculator — Estimate Wall Paint Needed

The Paint Calculator helps you estimate how much paint you need for any room or entire house. Add multiple rooms with dimensions, specify doors and windows for accurate deductions, set coating layers and coverage rate.

How It Works

Wall Area = 2 × (Length + Width) × Height. Door deduction = 21 sq ft each. Window deduction = 15 sq ft each. Gallons = (Paintable Area × Coats) ÷ Coverage per gallon.

Features

  • Multi-Room — Add as many rooms as needed.
  • Door/Window Deduction — Accurate area calculation.
  • Coat Layers — 1 to 5 coats supported.
  • Cost Estimate — Enter price per gallon for budget.

Privacy

All calculations run in your browser.

Frequently Asked Questions

How is door/window area deducted?

Standard door = 21 sq ft (3×7), standard window = 15 sq ft (3×5). These are deducted from total wall area.

What coverage should I use?

Most latex paint covers 350-400 sq ft per gallon. Check your paint can for exact coverage.

Should I use 1 or 2 coats?

2 coats is standard for most painting projects. Use 1 coat for touch-ups, 3 for dramatic color changes.

Is my data uploaded?

No. All calculations run 100% in your browser.