One Rep Max Calculator
Enter a weight you lifted and how many clean reps you did. The primary estimate is Epley; Brzycki is shown beside it.
How it works
Epley: 1RM = w × (1 + reps/30). Brzycki: 1RM = w × 36 / (37 − reps). Both are regression estimates from a submaximal set. They drift as reps climb; this page stops at 36. A single rep is reported as the weight itself.
Neither formula knows bar path, depth or fatigue.
Formula
Epley: 1RM = w × (1 + r/30) Brzycki: 1RM = w × 36 / (37 − r)
Worked examples
Epley 100 × 5
100 for 5 reps → about 116.7
Useful notes
- Not medical advice. Do not attempt a true max from a website number.
FAQ
- Which formula is “correct”?
Neither is exact. Epley is the headline figure; Brzycki is a second published check.
- Why cap reps at 36?
These equations were not built for very high-rep sets, and Brzycki’s denominator hits zero at 37.
- Should I test that 1RM in the gym?
Only with a plan and a spotter. This page is arithmetic, not coaching.
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