Health
One Rep Max Calculator
🔒 Werkt in je browser
Calculate your one-rep max (1RM) using the Epley formula — free, no account required, runs in your browser. Includes training percentage breakdowns for kg and lbs.
Hoe gebruik je deze tool
- Enter the weight you lifted and the number of clean reps you completed.
- The Epley formula estimates your one-rep max as weight × (1 + reps ÷ 30).
- Read your estimated 1RM plus a percentage table for programming your training loads.
Veelgestelde vragen
- Which formula is used?
- The Epley formula: 1RM = weight × (1 + reps ÷ 30). So 100 kg for 5 reps estimates about 117 kg.
- How many reps give a good estimate?
- Estimates are most reliable in the low-rep range — roughly 10 reps or fewer. The further past that you go, the less accurate the prediction.
- Why show training percentages?
- Programs often prescribe loads as a percentage of 1RM (for example 5 reps at 80%), so the table converts your estimated max into working weights.
- Is my lift data kept private?
- Yes. The weight and reps you enter are run through the Epley formula in your browser and are never uploaded or stored.