ZovaTool

One Rep Max Calculator

Estimated 1RM (avg of 7 formulas)
115.5 kg
Epley
116.7 kg
Brzycki
112.5 kg
Lander
113.7 kg
Lombardi
117.5 kg
Mayhew
119.0 kg
O'Conner
112.5 kg
Wathan
116.6 kg
% of 1RM training table (using avg 1RM)
1 reps · 100%115.5 kg
2 reps · 95%109.7 kg
3 reps · 93%107.4 kg
4 reps · 90%103.9 kg
5 reps · 87%100.5 kg
6 reps · 85%98.2 kg
7 reps · 83%95.9 kg
8 reps · 80%92.4 kg
9 reps · 77%88.9 kg
10 reps · 75%86.6 kg
12 reps · 70%80.8 kg
15 reps · 65%75.1 kg
20 reps · 60%69.3 kg
Formulas (w=weight, r=reps)
Epley: w × (1 + r/30)
Brzycki: w × 36 / (37 − r)
Lander: 100w / (101.3 − 2.67123 r)
Lombardi: w × r^0.10
Mayhew: 100w / (52.2 + 41.9 e^(−0.055 r))
O'Conner: w × (1 + 0.025 r)
Wathan: 100w / (48.8 + 53.8 e^(−0.075 r))

How to use the One Rep Max Calculator

  1. Enter weight lifted and clean reps performed.
  2. Use 2–10 reps for the most accurate estimate.
  3. Read your estimated 1RM from 7 formulas plus the % of 1RM training table.
Advertisement

1RM: the foundation of strength programming

Your one rep max is the heaviest weight you can lift for one full rep. Most programmes set intensity as a % of 1RM (e.g. 5×5 at 80%).

Testing a true 1RM is hard and risky. Submaximal estimation — lifting lighter weights for multiple reps and back-calculating — is safer and almost as accurate within 2–10 reps.

Epley and Brzycki are most popular. Mayhew and Wathan use exponential models and tend to be more accurate at higher rep counts. We average all seven to smooth outliers.