Paint Calculator

What is the Paint Calculator?

Estimate how many gallons of paint you need for a room. Estimating paint from wall area, openings and coats prevents buying too much or making a second trip mid-project.

How to use the Paint Calculator

1. Enter your room length, your room width, your wall height, your doors and the remaining fields.
2. Results update automatically as you type; you can also press Calculate.
3. Read the output: paint needed, gallons to buy, paintable wall area.
4. Use the 📊 chart to see the result visually, then copy or share it.

Formula and method

Worked example

With room length = 14 ft, room width = 12 ft, wall height = 8 ft, doors = 1, windows = 2, the Paint Calculator returns paint needed: 2.09 gal; gallons to buy: 3; paintable wall area: 365 ft².

Where the Paint Calculator helps in real life

You are painting a 12 × 14 ft bedroom with 8 ft ceilings, one door and two windows. The calculator gives the gallons needed for two coats.

You are comparing a premium paint with better coverage against a cheaper one. Using each brand’s coverage figure shows the real cost difference.

Common mistakes to avoid

• Planning only one coat for a big color change.
• Forgetting textured walls absorb more paint.
• Not subtracting doors and windows.
• Using a coverage figure from a different product.

💡 Practical tip: Dark colors, new drywall and bare wood often need primer or an extra coat.

Tips for better results

• Check the coverage per gallon on the can.
• Plan two coats for most color changes.
• Keep leftover paint labeled for touch-ups.

⚠️ Material estimates are approximate. Follow local building codes and manufacturer instructions.

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