One rep max calculator
Enter a recent hard set: the weight and how many clean reps you managed. You get an estimate of your one rep max without ever testing it, plus the loads that match common training percentages.
Estimated one rep max
114.6 kg
Epley 116.7 kg · Brzycki 112.5 kg
Training loads from your max
| % of 1RM | Load | About this many reps |
|---|---|---|
| 100% | 115 kg | 1 |
| 95% | 110 kg | 2 |
| 90% | 102.5 kg | 3 |
| 85% | 97.5 kg | 5 |
| 80% | 92.5 kg | 8 |
| 75% | 85 kg | 10 |
| 70% | 80 kg | 13 |
| 65% | 75 kg | 16 |
| 60% | 70 kg | 20 |
How the estimate works
The calculator averages two well-established formulas. Epley multiplies the weight by one plus a thirtieth of the reps; Brzycki divides 36 by 37 minus the reps. They agree closely between three and eight reps and drift apart above ten, which is why the result is shown with both.
Use a set you finished with good form and no more than one rep left in the tank. A set stopped far from failure underestimates your max; a set with a grinding last rep is the most accurate input you can give it.
Questions
Is an estimated one rep max accurate?
For sets of three to eight hard reps it is usually within a few percent of a tested max. It is less accurate for very high reps, and for lifts where technique breaks down near your limit.
Should I test my real one rep max?
Rarely. An estimate from a normal working set tells you almost as much, without the fatigue and injury risk of a true max attempt. Test only if you compete or need the exact number.
How do I use the percentage table?
Strength work usually sits at 80–90% for 3–6 reps, muscle building at 65–80% for 6–12. Start at the lower end of the load for a new program and let the reps tell you when to add weight.
Estimates for healthy adults, not medical or dietary advice. If you have a health condition, check with a professional.