🎨 Paint Calculator

This paint calculator estimates how much paint and how many cans you need to cover a room's walls, based on the wall dimensions, the number of doors and windows (which reduce the paintable area), and how many coats you plan to apply. It's built for homeowners, renters, and DIY painters who want a quick, reliable estimate before heading to the store, instead of guessing and either running short mid-project or overbuying.

How It Works

The calculator multiplies wall width by height by the number of walls to get the gross area, then subtracts a standard area for each door and window to get the net paintable area. That net area is multiplied by the number of coats and divided by your paint's coverage rate (how many square feet or square meters one gallon or liter covers) to get the total paint needed. Dividing that by your chosen can size and rounding up gives the number of cans to buy.

Why It Matters

Buying too little paint means an inconvenient second trip to the store — and possibly a slightly different batch or sheen. Buying too much wastes money on paint you won't use. A clear estimate of net area, total paint needed, and cans required helps you buy exactly what the job calls for, whether you're working in gallons and square feet or liters and square meters.

Tips for Accurate Results

• Use the actual coverage rate printed on your paint can label rather than the calculator's default — coverage varies by brand, paint type, and wall texture.
• Rough, textured, or unprimed walls absorb more paint, so consider lowering your coverage rate estimate for those surfaces.
• Two coats is standard for color changes or covering darker shades; a single coat may suffice for a fresh coat of the same color.
• Buy about 10% extra to cover touch-ups and small repairs later, since exact batch matching can be difficult months or years down the line.