One Rep Max (1RM) Calculator
Estimate your one-rep max from a set, with training percentages.
| 100% | 114.6 kg |
| 95% | 108.9 kg |
| 90% | 103.1 kg |
| 85% | 97.4 kg |
| 80% | 91.7 kg |
| 75% | 85.9 kg |
| 70% | 80.2 kg |
| 65% | 74.5 kg |
| 60% | 68.8 kg |
Estimates your one-rep max (the most you could lift for a single rep) from a set, averaging the Epley and Brzycki formulas. Estimates are least accurate above ~10 reps. Warm up and use a spotter for heavy attempts. Runs in your browser.
Results are general estimates for information only, not medical advice — consult a qualified professional for health decisions. See how we build our calculators.
Estimate your one-rep max — the most you could lift for a single repetition — from a set you've done, by averaging the Epley and Brzycki formulas. You also get a table of training percentages (60–100% of your 1RM) for planning working sets. Estimates are most accurate under about 10 reps. Warm up and use a spotter for heavy lifts.
How to use the One Rep Max Calculator
- Enter the weight you lifted and the number of reps.
- Read your estimated 1RM.
- Use the percentage table to plan training sets.
Frequently asked questions
How accurate is an estimated 1RM?
Quite accurate for sets of about 2–8 reps. Above ~10 reps the estimate drifts higher than reality, so use lower-rep sets for the best estimate.
What are training percentages for?
Programmes prescribe loads as a percentage of your 1RM (e.g. 5 reps at 80%). The table converts your estimated max into those working weights.