One-Rep Max Calculator
Estimate your one-rep max from any working set. Enter a weight and the reps you lifted — we compute 1RM with both the Epley and Brzycki formulas.
1RM (Epley)
116.7
1RM (Brzycki)
112.5
Average
114.6
95%108.9
90%103.1
85%97.4
80%91.7
75%85.9
70%80.2
65%74.5
60%68.8
Formula
Epley: 1RM = w × (1 + reps/30) · Brzycki: 1RM = w × 36/(37 − reps)How to use the One-Rep Max Calculator
- 1Enter the weight you lifted (kg or lb)
- 2Enter how many clean reps you completed
- 3Read your estimated 1RM from both formulas
Frequently Asked Questions
Which 1RM formula is more accurate?
Epley is the classic and slightly optimistic at high reps; Brzycki tends to be more accurate for sets under ~10 reps. If the two agree closely, you can trust the estimate.
Why estimate 1RM instead of testing it?
True max testing is exhausting and risky without a spotter. A submaximal set of 3–6 reps gives a solid estimate and far less recovery cost.