Contact
Questions about a formula, a suspected wrong result, or a calculator suggestion? Email us. There is no submission form; the button opens your email app.
Reporting a bug or wrong result
Please include: the calculator name or page address, the exact values you entered, whether Metric or Imperial was selected, the result shown, and the result you expected with how you worked it out.
Add your browser and device if the page looked broken. Do not send personal or payment information.
Paint coverage units
Enter paint coverage in m²/L in Metric or ft² per US gallon in Imperial. UK imperial gallons are not used.
Not covered
We cannot give engineering, structural or safety advice, or confirm supplier pack sizes.