Calculyn

One Rep Max Calculator

Estimate your one-rep max from a weight you can lift for several reps.

lb

Results update as you type.

Estimated one-rep max

216lb
90% of max
194
80% of max
173
70% of max
151
Estimated one-rep max216

This is an educational estimate, not medical advice. Talk to a healthcare professional about your situation.

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How it works

Uses the Epley formula, which is most accurate for sets of 2–10 reps. Training percentages help plan working sets.

Formula

1RM = Weight × (1 + Reps ÷ 30)

Example

185 lb for 5 reps → 185 × (1 + 5/30) ≈ 216 lb.

Assumptions & limitations

  • Results are rounded for display.

Frequently asked questions

Should I test my true max?

Only with a spotter and good form. The estimate is a safer way to plan training.