One-Rep Max Calculator

1RM from reps with 7 formulas and training zones. Free, private and instant.

How to use the One-Rep Max

  1. Pick metric (cm, kg) or imperial (ft, in, lb) units.
  2. Enter weight lifted.
  3. Enter repetitions completed (reps).
  4. Press Calculate to get an instant result with a colour scale, chart and plain-English explanation.

About the One-Rep Max

Estimate the heaviest weight you could lift for one repetition without risky max attempts. Enter the weight and number of reps you completed and compare seven well-known formulas, with training zones for strength, size and endurance.

Also known as: 1RM calculator, max lift calculator, Epley calculator, Brzycki calculator, bench press max calculator.

Worked example

Estimated 1-rep max: 80.8 kg (from 70.0 kg x 5). Your estimated one-rep max is about 80.8 kg. Around 85 to 95% of it is typical for strength work.

Formula and cut-offs

Epley: w(1 + r/30). Brzycki: 36w/(37 - r). Lander: 100w/(101.3 - 2.67123r). Lombardi: w x r^0.10. Mayhew, O’Conner and Wathan are also averaged.

Frequently asked questions

How do I calculate my one rep max?

Lift a weight for 3 to 10 hard reps and use a formula such as Epley: weight x (1 + reps / 30).

What percent of 1RM is best for muscle growth?

About 65 to 85% of 1RM, for 6 to 12 reps.

Is estimating safer than testing?

Yes, because you avoid maximal single lifts.

What is my one-rep max if I lift 70 kg for 5 reps?

Estimated 1-rep max: 80.8 kg (from 70.0 kg x 5). Your estimated one-rep max is about 80.8 kg. Around 85 to 95% of it is typical for strength work. Enter your own numbers above for a personal result.

Sources and references

Written and checked by the MediHub editorial team against the sources above. Read how we build and review our calculators.

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Last updated . This calculator is for education only and is not medical advice. See the medical disclaimer.