Coatly: Paint Calculator

Paint estimator that shows its work. Enter your walls, get gallons or liters plus the exact cans to buy — every step of the math on a receipt. Offline, no account.

How much paint do I need? Coatly is a paint estimator that answers in cans, not decimals — and shows every line of the math. Enter your walls (or a whole room), get gallons or liters, primer, and the exact 1-gal, quart, and 5-gal cans to buy.

Ideal for homeowners, weekend DIY, landlords, and anyone repainting a room for the first time.

WHAT YOU GET • The amount you need, in gallons or liters • A purchase guide in real can sizes — 1-gal, quart, 5-gal • A receipt-style breakdown of the whole calculation • Primer, surface texture, and extra-coat adjustments • Optional ceiling, added as its own surface • Instant switching between feet and meters, gallons and liters

HOW IT WORKS

1. Add your walls — one at a time, or enter a room's width, length, and height for all four at once. Subtract doors and windows with a tap.
2. Confirm the conditions: number of coats, wall surface, whether you're covering a dark color, and the coverage printed on your paint can.
3. Get your answer.

WHY THE RECEIPT MATTERS The most common complaint about paint calculators is that you can't tell whether the number is right. Coatly answers that by never hiding a step. You see the total wall area, what was deducted for doors and windows, the net area, the multiplication for coats, the division by coverage, the buffer, and the final amount — each as its own line with its own number. If something looks off, you can find exactly where it came from and fix the input.

ACCURACY How accurate is it? As accurate as the coverage figure on your can — Coatly uses the number you enter, not a one-size-fits-all average. Rough or textured walls, a dark color underneath, primer, and a second coat each adjust the total, and each adjustment is its own line on the receipt.

Does it subtract doors and windows? Yes — tap to add each opening and it's deducted from the wall area before anything else is calculated. Does it include the ceiling? Optional. Turn on "Include ceiling" and it's added as its own surface.

CANS, NOT DECIMALS Paint isn't sold in decimals. When your estimate is 2.4 gallons, Coatly tells you to buy two 1-gallon cans and two quarts — 2.5 gallons in total. The purchase total is always at least what you need, never less. Running out halfway up a wall means a second trip and a visible seam, so every rounding decision in the app goes the same direction: up.

COATLY PREMIUM A one-time purchase — not a subscription. It unlocks: • Multi-room projects with a combined total and a single purchase guide • Cost estimates based on the cans you'll actually buy • Saved projects you can come back to • No ads

PRIVATE BY DESIGN Coatly runs entirely on your device. Your measurements, projects, and prices never leave your phone — there's no account, no server, and no sync. The free version shows ads, which are provided by Google AdMob; the privacy policy explains what that involves.

Estimates are guidance. Actual coverage varies with the product, the surface, and how it's applied — always check the coverage figure on the can you're buying.