Health & Fitness

One-Rep Max Calculator

Estimate one-repetition maximum (1RM) from a lifted weight and repetition count using common strength formulas.

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How to use this one-rep max calculator

Enter the requested values above and select Calculate. Change any input to compare scenarios instantly.

Formula and method

Estimates 1RM using Epley, Brzycki and Lombardi formulas and shows their average.

Example

If you lift 185 lb for 8 repetitions, the calculator estimates a one-rep maximum from multiple formulas.

What this calculator is useful for

Estimate one-repetition maximum (1RM) from a lifted weight and repetition count using common strength formulas. Use it for quick estimates and comparisons; verify high-stakes health, training or measurement decisions with an appropriate authoritative source.

Frequently asked questions

What does the One-Rep Max Calculator calculate?

Estimate one-repetition maximum (1RM) from a lifted weight and repetition count using common strength formulas.

How does the calculation work?

Estimates 1RM using Epley, Brzycki and Lombardi formulas and shows their average.

Is this calculator free?

Yes. ERICH Calculators is free to use and no account is required.

Source & assumptions

Reference and limitation

1RM equations are training estimates. Do not attempt a maximal lift solely from a calculator result; use appropriate technique, spotting and coaching.

Transparency

Method, assumptions & corrections

See how formulas, sources and limitations are handled across ERICH Calculators.