One-Rep Max (1RM) & Training Percentage Calculator

A one-rep max is the heaviest load you can lift for a single repetition, and it anchors percentage-based programming. Rather than testing a true max, submaximal sets are converted using regression formulas. Epley tends to read slightly higher at high rep counts while Brzycki reads lower, so averaging the two gives a more stable estimate across the common 3–8 rep range. Worked example: lifting 100 kg for 5 reps gives an Epley estimate of 100 × (1 + 5 ÷ 30) = 116.7 kg and a Brzycki estimate of 100 × 36 ÷ (37 − 5) = 112.5 kg, so your one-rep max is roughly 112 to 117 kg. The estimates are less accurate above about 10 reps, so use a set of 3 to 6 reps when you can. Work up gradually and use a spotter before attempting a maximum.