Strength
Strength
Powerlifting
Estimation
1RM Calculator
🧮 About this calculator
Predicts your one-rep maximum (1RM) from a submaximal set. Accurate within +/-5% for 2-10 rep sets. The Epley formula is used as default — most accurate for most people.
Inputs
📘 Formula & explanation
Epley: 1RM = weight * (1 + reps / 30)
Epley (1985) is widely used and accurate for reps in the 2-10 range. For higher reps (>10), the formula overestimates 1RM.
References
- Epley B (1985)
- Brzycki M (1993)
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