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Evidence-Based Biomechanics Formula

One Rep Max (1RM) Calculator

Compute your theoretical single-rep maximum load using the validated Epley and Brzycki sports science formulas without risking injury with true maximal attempts.

Weight Unit
The exact weight used on your working set.
5 reps
1 (True 1RM)5 (Heavy)10 (Hypertrophy)15 (Endurance)
Formula accuracy is highest for sets between 1 and 10 repetitions. Beyond 10 reps, cardiovascular fatigue skews true maximal strength estimates.
Calculated Average 1RM
114.6kg

Composite estimate blending Epley and Brzycki formulas for maximum precision.

Epley Formula
116.7 kg
w × (1 + r/30)
Brzycki Formula
112.5 kg
w × (36 / (37 - r))
Estimated 5RM Target
99.7 kg
~87% of 1RM
Percentage of 1RM Load ReferenceWeight (KG)
95%
108.9 kg
90%
103.1 kg
85%
97.4 kg
80%
91.7 kg
75%
85.9 kg
70%
80.2 kg
65%
74.5 kg
60%
68.8 kg

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