One-rep max calculator
Enter the weight and reps to estimate your 1RM and training percentages.
One-rep max calculator
Estimate your one-rep max (1RM) — the most weight you could lift for a single rep — from a set you’ve already done. The table then shows training loads at 95% down to 70%, so you can program your sessions.
Formula
This uses the Epley formula: 1RM = weight × (1 + reps ÷ 30). Example: 80 kg for 5 reps ≈ 93 kg. Estimates are most accurate at 10 reps or fewer.
Training percentages
- ~95%: strength (2–3 reps).
- ~80%: strength/hypertrophy (6–8 reps).
- ~70%: hypertrophy/volume (10–12 reps).
Frequently asked questions
How do I calculate my one-rep max? Multiply the weight by (1 + reps ÷ 30). Don’t test a true 1RM without warming up and a spotter.
Is the estimate accurate? Within a few percent for sets under 10 reps; less reliable for very high-rep sets.