Fitness
One-Rep Max Calculator
Estimate your 1RM from any weight and reps using Epley, Brzycki, Lombardi, and O'Conner formulas. Plus training percentages.
Your set
Estimated 1RM (average of 4 formulas)
114.8 lb
Epley
116.7 lb
Brzycki
112.5 lb
Lombardi
117.5 lb
O'Conner
112.5 lb
Training percentages
95%
109 lb
~2 reps
90%
103.3 lb
~4 reps
85%
97.6 lb
~6 reps
80%
91.8 lb
~8 reps
75%
86.1 lb
~10 reps
70%
80.3 lb
~12 reps
65%
74.6 lb
~15 reps
60%
68.9 lb
~20 reps
50%
57.4 lb
~25 reps
Frequently Asked Questions about the One-Rep Max Calculator
Which 1RM formula is most accurate?
Epley and Brzycki are the most widely cited and agree within 2-3% for sets of 1-8 reps. Lombardi and O'Conner cover different rep-range assumptions. Because no single formula is universally best, this calculator shows all four results plus the mean so you can see how closely they cluster, or where they diverge.
Why is Brzycki excluded for sets over 10 reps?
Brzycki's formula uses a 36 / (37 - reps) multiplier that grows without bound as reps approach 37. Above 10 reps it inflates the 1RM estimate significantly, so the calculator drops it from the average and shows it as unavailable, keeping the result grounded in the three remaining formulas.
How accurate is a calculated 1RM versus an actual max test?
For sets of 3-6 reps, estimates typically land within 5% of a true 1RM. Accuracy falls off at higher rep counts and for newer lifters whose fatigue curve doesn't match the formulas. Treat the result as a solid planning number, not a guaranteed max, and keep a spotter handy if you ever test it for real.
What are the typical percentages used for training?
Strength work generally sits at 80-95% of 1RM for 1-6 reps. Hypertrophy work uses 65-80% for 6-12 reps. Speed and power work uses 50-70% at high movement velocity. The percentage table below your result shows estimated rep counts at nine loads from 50% to 95% of your calculated max.
Should I really test my 1RM in the gym?
Not unless you need an exact number for competition. Most lifters get more out of training in the 3-8 rep range and calculating max from there, with lower injury risk, more practice reps, and an estimate that is usually close enough for programming. If you do test, use a spotter, complete a thorough warm-up, and stop the moment form breaks down.