One-rep max (1RM) calculator
Estimate your one-rep max (1RM) and the loads to train at different intensities.
Estimated 1RM
101.3 kg
90% (strength)91.2 kg
80% (hypertrophy)81.1 kg
70% (endurance)70.9 kg
Epley formula. Estimate — do not attempt a true 1RM without supervision and warm-up.
How the calculation works
1RM is the max load you could lift once. The Epley formula estimates: 1RM = weight × (1 + reps ÷ 30). The percentages help plan training.
Frequently asked questions
How many reps to use?
The estimate is more accurate with up to ~10 reps.
Related calculators
Updated on June 18, 2026 · by Rafael Rossi · Methodology & sources