One Rep Max Calculator
Estimate the maximum weight you can lift for one repetition.
Result
Results are estimates for general information only and are not professional advice.
Your one rep max
Your one-rep max (1RM) is the most weight you can lift once. This calculator uses the Epley formula to estimate it from a set you performed, and shows useful training percentages (95%, 90%, 85%…).
Frequently Asked Questions
What is the One Rep Max Calculator?
Estimate the maximum weight you can lift for one repetition. It runs instantly in your browser and is completely free to use.
What do I need to enter to use the One Rep Max Calculator?
The One Rep Max Calculator asks for the following values (2): Weight lifted, Repetitions. Fill them in and the result appears immediately — the calculation runs on your own device, so nothing you type is sent to a server.
How accurate is the One Rep Max Calculator?
The One Rep Max Calculator uses standard, widely-accepted formulas, so its figures are reliable estimates for everyday planning. They are not a substitute for advice from a qualified professional.
Is the One Rep Max Calculator free, and do I need an account?
Yes. The One Rep Max Calculator — and every other calculator on Calculatis — is completely free, with no registration, no download and no limit on how often you use it.