How to Use One Rep Max (1RM) Calculator
Estimate your one-rep max from weight and reps, with training percentage breakdowns.
Open the One Rep Max (1RM) Calculator tool →What is One Rep Max (1RM) Calculator?
Estimate your one-rep max from weight and reps, with training percentage breakdowns. It's completely free, needs no sign-up, and runs entirely in your browser — so it's fast and private.
How to use One Rep Max (1RM) Calculator
- Open the One Rep Max (1RM) Calculator tool.
- Enter your details or values.
- The result is calculated instantly.
- Copy or use the result. Everything runs in your browser — nothing is uploaded.
Frequently asked questions
How is my 1RM estimated?
From the weight and reps using the Epley and Brzycki formulas, averaged. It's most accurate for sets of 1-10 reps.
Should I test my true max?
The estimate is a safe guide. If you attempt a real 1RM, warm up thoroughly and use a spotter or safety bars.
Ready to try it?
Open One Rep Max (1RM) Calculator →