One-Rep Max (1RM) Calculator + Training Loads
Estimate your one-rep max from a weight and reps using the Epley and Brzycki formulas, with a percentage table of training loads. In your browser.
Training loads
| of 1RM | kg |
|---|---|
| 95% | 108.9 |
| 90% | 103.1 |
| 85% | 97.4 |
| 80% | 91.7 |
| 75% | 85.9 |
| 70% | 80.2 |
| 65% | 74.5 |
| 60% | 68.8 |
| 55% | 63 |
| 50% | 57.3 |
🔒 Calculated in your browser. Epley & Brzycki estimates — real maxes depend on form, fatigue and the lift. Don't attempt a true max without a spotter.
Estimate your max without maxing out
Enter a weight you lifted and how many reps you managed, and the tool estimates your one-rep max (1RM) with the Epley and Brzycki formulas plus their average. It also builds a percentage table (50–95% of 1RM) so you can pick training loads for your program.
An estimate, lift safely
Rep-based estimates get less accurate as reps climb (best under about 10), and real maxes depend on form, fatigue and the lift itself. Use the numbers to program training, and never attempt a true one-rep max without a spotter or safeties. Everything runs in your browser.
Frequently asked questions
How is one-rep max calculated?
From a submaximal set: Epley = weight × (1 + reps/30); Brzycki = weight × 36 ÷ (37 − reps). 100 kg × 5 reps is about 113–117 kg.
How accurate are 1RM estimates?
Good for low reps (roughly under 10) and rougher above that. They’re a training guide — form and fatigue affect a real max.