Gauritanaya

One-rep max calculator

From a set you’ve done, estimate the most you could lift once, without testing it.

Runs entirely in your browser. Nothing you type is sent anywhere.

reps

Use a set taken close to failure, ideally 10 reps or fewer.

Estimated one-rep max—

Epley
—
Brzycki
—

Training weights

% of 1RMWeight

For general wellness only. These results are estimates from published formulas and guidelines, not a diagnosis or medical advice. They may not suit pregnancy, children, older adults, athletes or people with health conditions. Talk to a qualified health professional about your health. In an emergency, call your local emergency number.

How to use the one-rep max calculator

Epley (1985): 1RM = weight × (1 + reps ÷ 30). Brzycki (1993): 1RM = weight × 36 ÷ (37 − reps). The result shown is the average of the two. Both are most accurate for sets of up to about 10 reps; above that they drift apart.

  1. Enter the weight you lifted and the unit.
  2. Enter how many reps you completed.
  3. Read your estimated one-rep max and the training weights table.

Sources

Sources checked on 9 October 2026. Formulas and thresholds are used as published; the wording on this page is our own.

Questions

Should I test my real one-rep max?
Not without a spotter and good technique. Estimating from a set of 3–8 reps is safer for most people.
Why do the two formulas differ?
They were fitted to different groups of lifters. They agree closely at low reps and differ more as reps increase.
Is this a diagnosis?
No. It compares your numbers with published ranges for general wellness. Only a qualified health professional can assess your health, taking your history and other tests into account.

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