One-Rep Max Calculator
Estimate your one-rep max and training weights at every percentage.
Estimates lose accuracy past ~12 reps and depend on the set being taken close to failure with good form. Not a substitute for testing under a coach's supervision.
Estimated 1RM (Epley)
117 kg
Estimated 1RM (Brzycki)
113 kg
Training percentage chart
Based on the Epley estimate
For informational and educational purposes only — not medical advice, and not a substitute for consulting a qualified professional about your specific situation. TrueMeasureKit is not liable for decisions made based on these results. See our Terms of Service.
Epley vs. Brzycki
Both formulas estimate your true one-rep max from a lighter set taken close to failure. Epley (weight × (1 + reps/30)) tends to estimate slightly higher at higher rep counts; Brzycki (weight × 36/(37 − reps)) tends to track closer at lower rep ranges. Neither replaces an actual tested max, but both are accurate enough to program training percentages without maxing out every session — useful since frequent true 1RM attempts carry more injury risk and central nervous system fatigue than submaximal training.
Frequently asked questions
How is one-rep max estimated from multiple reps?
Using an established formula (such as Epley or Brzycki) that extrapolates from the weight and rep count of a set performed close to failure — it's an estimate, since true 1RM depends on factors like fatigue and technique on the day.
Why do the percentage-based training weights matter?
Structured strength programs are often prescribed as a percentage of 1RM (e.g., "work up to 5 reps at 80% of 1RM") — having your estimated max lets you calculate the actual weight to load without repeatedly testing a true max, which carries injury risk.