TOOLS — GYM & FITNESS

One Rep Max (1RM) Calculator

Enter the weight you lifted and how many reps you completed. Get your estimated 1RM from three validated formulas, plus a complete training percentage table.

Your Lift
Weight Lifted
in pounds or kg (consistent units)
Reps Completed
reps performed (1–30)
Unit System
ESTIMATED 1RM
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BY FORMULA
TRAINING PERCENTAGES
%1RMWeightTarget RepsBest For
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About These Formulas

Brzycki (1993): w / (1.0278 − 0.0278 × r) — most accurate for sets of 10 reps or fewer. Widely used in strength sports.
Epley (1985): w × (1 + r/30) — tends to estimate slightly higher; good for 5–15 rep ranges.
Lombardi (1989): w × r0.10 — conservative estimate, useful as a lower bound. All estimates are less accurate above 10 reps — keep sets to 1–5 reps for best 1RM accuracy.