One Rep Max Calculator
1RM Estimates
117 kg
Epley
113 kg
Brzycki
114 kg
Lander
115 kg
Average
Training Percentages (based on Epley 1RM)
105
90%
94
80%
82
70%
70
60%
59
50%
What is One Rep Max (1RM)?
Your 1RM is the maximum weight you can lift for a single repetition with proper form. It is the gold standard for measuring absolute strength. Rather than testing your 1RM directly (which carries injury risk), these formulas estimate it from a submaximal set.
Most accurate with 3–10 reps. Estimates become less reliable above 12 reps.
Frequently Asked Questions
Which formula is most accurate?
The Epley formula is most widely used. Brzycki is generally more accurate for lower rep ranges (under 10 reps). The average of all three provides a reasonable estimate. Accuracy decreases as reps increase beyond 10.
Should I actually test my 1RM?
Only experienced lifters should attempt true 1RM testing, with a spotter, after proper warm-up. For most people, formula-based estimates are sufficient for programming training percentages without the injury risk.
How do I use my 1RM for programming?
Training programs typically prescribe percentages of 1RM. For hypertrophy (muscle growth): 65–85%. For strength: 80–95%. For power: 55–80%. The percentage chart in the results section shows exact weights for common training zones.
Formulas
Epley: w(1 + r/30)
Brzycki: w×36/(37−r)
Lander: 100w/(101.3−2.67r)