1RM Calculator

Calculate your One-Rep Max (1RM) to optimize your strength training.

For best accuracy, use a weight you can lift 10 times or less.

Reps to Percentage Reference

Reps % of 1RM Training Goal
1 100% Max Strength
2-3 90-95% Power / Strength
4-6 85-90% Strength / Hypertrophy
8-12 65-80% Hypertrophy (Muscle Growth)
15+ < 60% Endurance

Ready to put these numbers to work?

Download our customizable Interval Timer App. Perfect for HIIT, Tabata, and keeping your workouts on track anywhere, anytime.