Estimate your one-rep maximum from a submaximal set. Useful for programming percentages and progressive overload.
Formulas such as Epley (weight × (1 + reps/30)) and Brzycki (weight × 36/(37−reps)) estimate the maximum weight you could lift for one clean rep. Accuracy is best with 1–10 reps. Sets above 12 reps are less reliable for 1RM prediction.
Enter a weight you lifted and the number of reps you completed. Formulas such as Epley (weight × (1 + reps/30)) and Brzycki estimate your 1RM. Sets of 1–10 reps are the most accurate.
1RM ≈ weight × (1 + reps ÷ 30). Example: 100 kg for 5 reps → 100 × (1 + 5/30) = 116.7 kg. This calculator also shows the Brzycki estimate and an average of both.
Strength work often uses 80–90% of 1RM for low-rep sets. Hypertrophy ranges commonly sit around 65–80% of 1RM. Recalculate as you get stronger.
It is a useful estimate, not a lab measurement. Beginners improve quickly, so treat the number as a guide for programming and update it every few weeks.