Paint Calculator

Calculate exactly how much paint you need for any room. Enter room dimensions, subtract doors and windows, and pick your number of coats.

Standard paint coverage: 350 sq ft / gal
Standard door: 20 sq ft
Standard window: 15 sq ft

About Paint Calculator

This free paint calculator helps you determine exactly how much paint you need for any room. Simply enter your room dimensions, subtract standard door and window areas, and choose how many coats you plan to apply. The calculator accounts for paint coverage rates and shows results in gallons, quarts, or liters — with specific can size recommendations. Whether you are painting a bedroom, living room, or hallway, get an accurate estimate in seconds, no account needed.

Free & Unlimited

Use as many times as you need. No account, no sign-up, no tracking — just pure calculation.

Instant Results

Get your paint estimate immediately with a single click. No page reloads, no waiting.

Privacy First

All calculations happen in your browser. Your room dimensions never leave your device.

Accurate Formulas

Uses standard paint coverage rates (350 sq ft/gal) with proper door and window subtraction.

📋 Common Use Cases

DIY Home Renovation

Plan paint, flooring, or fencing projects with precise material estimates. Know exactly how many gallons, boxes, or bags to buy before heading to the hardware store.

Contractor Bid Verification

Double-check contractor material estimates to ensure you are not overpaying. Understand the math behind their quotes for framing, roofing, or concrete work.

Landscaping Projects

Calculate mulch, soil, or gravel needed for garden beds and landscaping. Enter irregular shapes and depths for accurate cubic yard estimates.

Budget Planning

Use material quantity estimates to build accurate project budgets. Factor in waste percentages and compare material costs across different product options.

🪜 How to Use This Tool

  1. Measure your space
    Enter length, width, and height/depth in feet or meters. For irregular spaces, break the area into rectangles and calculate each separately.
  2. Configure material specifications
    Select material type, coverage rate, bag size, or waste factor. Each calculator uses industry-standard coverage rates for its specific material.
  3. Review material estimates
    See total area, material quantity in standard units (gallons, bags, cubic yards), and estimated cost range based on typical retail prices.
  4. Adjust for your project specifics
    Add extra for waste, multiple coats, or pattern matching. Round up to full units — it is always better to have a small surplus than to run short mid-project.

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Frequently Asked Questions

Are these calculators really free?▼
Yes. All calculators on iluv.tools are completely free. No signup, no account, no credit card required. Every calculation runs instantly in your browser.
Is my data sent anywhere?▼
Absolutely not. All calculators are pure client-side JavaScript. Your numbers, dates, and inputs never leave your browser. No server processing, no tracking.
How accurate are these calculators?▼
Calculators use standard mathematical formulas with double-precision floating point. Results match industry-standard financial and scientific calculations.
Can I use calculators on mobile?▼
Yes. All calculators work on mobile browsers (iOS Safari, Android Chrome) with responsive layouts.