About the One Rep Max Calculator
Estimate the most weight you can lift for one repetition. This tool is free, works in your browser and needs no sign-up.
How to use the One Rep Max Calculator
Enter the weight you lifted and the number of reps you did. Results are most accurate for 10 reps or fewer.
Formula used
Epley: 1RM = weight × (1 + reps ÷ 30). Brzycki: 1RM = weight × 36 ÷ (37 − reps).
Example
With Weight lifted 80, Reps 5, the calculator shows: Epley = 93.3; Brzycki = 90.0.
Frequently asked questions
Is the One Rep Max Calculator free to use?
Yes. It is completely free and you can use it as many times as you like.
How accurate is the One Rep Max Calculator?
The calculator uses standard formulas, so the maths is exact. Real life results can differ because of fees, taxes, rounding or personal factors, so treat the answer as an estimate.
Do you store the numbers I enter?
No. All calculations run in your browser. The values you type are not sent to our server.
Disclaimer: results are estimates for information only. They are not financial, medical or professional advice.