One Rep Max Calculator
Estimated 1RM from a set, plus a full percentage training table.
Last updated
Your details
Result
- Estimated one rep max
- 114.6 kg
- Epley formula
- 116.7 kg
- Brzycki formula
- 112.5 kg
Average of the Epley and Brzycki formulas
How 1RM is estimated
The Epley formula is weight × (1 + reps ÷ 30); Brzycki is weight × 36 ÷ (37 − reps). They agree closely at low rep counts and diverge as reps climb, which is why this calculator averages them and warns above fifteen.
Accuracy is best from sets of two to five taken close to failure. A set of twelve depends heavily on muscular endurance, which varies far more between people than maximal strength does.
Using the percentage table
Most strength programmes prescribe load as a percentage of 1RM. The table above converts your estimate into working weights and the rep count each percentage typically supports.
Treat it as a starting point that needs adjusting. Bench press and squat percentages behave differently — most lifters can complete more reps at a given percentage on squats than on bench.
Formula & methodology
What this calculator assumes
- Estimates are most accurate from sets of two to five taken close to failure, and unreliable above about fifteen repetitions.
- Percentage-to-rep relationships differ by lift; most lifters complete more reps at a given percentage on squats than on bench press.
Sources
- Epley B. Poundage Chart. Boyd Epley Workout. University of Nebraska, Lincoln, 1985.
- Brzycki M. Strength testing: predicting a one-rep max from reps to fatigue. Journal of Physical Education, Recreation & Dance, 1993;64(1):88–90.
Frequently asked questions
Should I test my actual 1RM?
Rarely, and only with experience and a spotter. True maximal attempts carry real injury risk and require days of recovery; estimating from a heavy triple gives nearly the same information at a fraction of the cost.
Which rep range gives the best estimate?
Between three and six reps. Below three there is little to extrapolate from, and above about ten the estimate depends increasingly on muscular endurance rather than maximal strength, which varies enormously between people and between lifts.
Why do the formulas disagree with each other?
Because they were fitted to different populations and different lifts. Epley tends to read higher at high rep counts, Brzycki lower. The spread between them is a fair picture of the genuine uncertainty, which is why showing one number alone would overstate how much is known.
Does the estimate hold across different exercises?
Roughly, for compound barbell lifts. It is least reliable for the bench press at high reps and for anything where technique breaks down before the muscle does — the formula assumes the limiting factor is strength, not stability or grip.
Training percentages
| % of 1RM | Weight | Approx. reps |
|---|---|---|
| 100% | 114.6 kg | 1 |
| 95% | 108.9 kg | 2 |
| 90% | 103.1 kg | 4 |
| 85% | 97.4 kg | 6 |
| 80% | 91.7 kg | 8 |
| 75% | 85.9 kg | 10 |
| 70% | 80.2 kg | 12 |
| 65% | 74.5 kg | 16 |
| 60% | 68.8 kg | 20 |