1RM Calculator

This calculator estimates your one-rep max (1RM) — the maximum weight you can lift for a single repetition — based on a set you've actually performed.

Epley: weight × (1 + reps/30). Best for moderate rep ranges (3–10).

Brzycki: weight × 36/(37 − reps). Most accurate for lower rep ranges (1–6).

Lombardi: weight × reps^0.1. Tends to give slightly lower estimates.

The average of all three formulas gives the most reliable estimate. For best accuracy, use a set of 3–6 reps performed with good form to near failure.