One Rep Max (1RM) Calculator
Enter a weight and the reps you did to estimate your one-rep max (1RM). We show both the Epley and Brzycki estimates plus a percentage table so you can program every set.
Your results
| 95% | 109 kg |
| 90% | 104 kg |
| 85% | 98 kg |
| 80% | 92 kg |
| 75% | 86 kg |
| 70% | 81 kg |
| 65% | 75 kg |
| 60% | 69 kg |
How it works
- 1Your 1RM is estimated from the weight and reps of a hard set using the Epley and Brzycki formulas.
- 2Estimates are most accurate under about 10 reps; higher reps introduce more error.
- 3Use the percentage table to load your working sets (for example 5x5 at ~80%).
Frequently asked questions
How is one-rep max calculated?
It is estimated from the weight and repetitions of a submaximal set. The Epley formula (weight x (1 + reps/30)) and Brzycki formula are the two most common, and averaging them is reliable under 10 reps.
How accurate is a 1RM estimate?
Very accurate for sets under about 6 reps, and still useful up to 10. Beyond 10 reps, differences in endurance make the estimate less reliable.
Should I test my true 1RM?
Rarely. An estimated 1RM from a calculator is safer and good enough to set training percentages. Save true max attempts for competitions or occasional testing with a spotter.
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