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 cited and tend to agree within 2 to 3% for sets of 1 to 8 reps. Lombardi and O'Conner round out the average. This calculator shows all four plus the mean to smooth out individual bias.
Why is Brzycki excluded for sets over 10 reps?
Brzycki uses a 36 over (37 minus reps) ratio that diverges sharply as reps approach 12. Past 10 reps it overestimates 1RM by a wide margin, so the calculator drops it from the average to keep results sensible.
How accurate is a calculated 1RM versus an actual max test?
Estimates are typically within 5% of a true 1RM for sets of 3 to 6 reps. Accuracy drops at higher rep ranges and for less experienced lifters. For programming, the calculated max is usually accurate enough.
What are the typical percentages used for training?
Strength work sits at 80 to 95% of 1RM for 1 to 6 reps. Hypertrophy work uses 65 to 80% for 6 to 12 reps. Power work uses 50 to 70% at high speed. The table below your result shows reps for each percentage.
Should I really test my 1RM in the gym?
Only with a spotter, after a proper warm-up, and with solid technique on the lift. Most lifters get better results training in 3 to 8 rep ranges and estimating max from there. Form failure under a true max is risky.
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