Coatly tells you how much paint to buy — and shows you exactly how it got there, line by line, like a receipt.

Contact us

Email [email protected]

We aim to reply within 2 business days. To help us help you faster, please include:

• Your device and OS version (for example, iPhone 15, iOS 18.2)
• The Coatly version number, shown at the bottom of the Settings screen
• What you entered and what you expected to see

Frequently asked questions

How does Coatly calculate the amount?

Every number on the result screen comes from one formula:

Paint needed = (paintable area × coats) ÷ effective coverage × (1 + buffer)

• Paintable area = the sum of your wall areas, minus every door and window you added
• Effective coverage = the coverage you entered, adjusted for the wall condition
• Buffer = 10% extra, on by default

The receipt on the result screen shows each of these steps with its actual number, so you can check the math yourself before you spend money.

Why does the app round everything up?

Running out of paint halfway through a wall is the worst outcome — you lose a day, and a new can may not match the batch you started with. So Coatly always rounds in the direction of slightly too much rather than slightly too little. This applies to the final volume and to the can combination.

What is the 10% buffer, and can I turn it off?

The buffer covers touch-ups, spills, roller absorption, and uneven spots. It is on by default.