One-Rep Max Calculator
A free, browser-based calculator. Runs entirely in your browser — no sign up, nothing stored.
100% FreeRuns in your browserBasic
Enter Values
Enter your values and press Calculate to see results.
How to use this calculator
- Enter the weight lifted and reps.
- Press Calculate.
How it works
Estimates the most you could lift once from a lighter set, using the Epley formula: weight × (1 + reps ÷ 30).
Worked example
100 kg for 5 reps. ≈ 117 kg.
Related tools
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.