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One-Rep Max Calculator

Estimate a one-rep maximum from a completed set and explore percentage loads without attempting a maximal lift.

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Interactive tool

Estimate from a completed set

Total load lifted(kg)

Repetitions completed

Use a recent set of 1–10 reps with consistent technique. Include the bar weight. Estimates vary with the exercise and how close the set was to your repetition limit.

Results update as you change the inputs.

Estimated one-rep maximum

67.5 kg

Percentage examples, not a workout prescription
% of estimate	Total load
60%	40.5 kg
70%	47.3 kg
80%	54 kg

Brzycki estimate. Not a safe lifting limit; no maximal test is required.

How the estimate works

Brzycki estimate = total load × 36 ÷ (37 − completed repetitions). This tool accepts sets of 1–10 reps; a single rep returns the load you entered.

Use an existing set performed with consistent technique, close to your repetition limit. Include the bar in a barbell load. For paired dumbbells, use their combined load consistently. Results vary by exercise and person.

An estimate is not a safe lifting limit or a training prescription. Percentage loads are illustrative. Do not attempt a maximal lift just to test this result; seek qualified coaching for technique and progression.

Published Brzycki equation: study methods, equation 1

Method reviewed against the linked source · 30 September 2026

Good to know

This calculator stops at 10 reps to limit extrapolation. Use a recent, technically sound set in the accepted range; there is no need to perform a new maximal test.

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