One Rep Max Calculator
Calculate your estimated one rep max using multiple proven formulas. Get a complete percentage chart for your training.
💡 Tip
Use a weight you can lift for 2-10 reps for best accuracy. Formulas become less accurate above 10 reps.
0 kg
Based on 100 kg × 5 reps
Epley
kg
Brzycki
kg
Lombardi
kg
O'Conner
kg
Training Percentages
Safety Note
These are estimates. Never attempt a true 1RM without proper warm-up, a spotter, and experience. Use the percentage chart as training guidelines.
The Formulas
Epley
1RM = W × (1 + R/30)
Brzycki
1RM = W × (36 / (37 - R))
Lombardi
1RM = W × R^0.10
O'Conner
1RM = W × (1 + R/40)
About the One Rep Max Calculator
This one rep max calculator estimates health and fitness metrics from your personal inputs. Estimate your 1RM using multiple proven formulas.
Use for personal wellness tracking and education. Consult a healthcare provider for medical advice.
Adjust the inputs above to model your specific scenario with the One Rep Max Calculator.
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