1RM Calculator

Calculate your one-rep max (1RM) and get personalized training zones

Calculator Inputs

Choose a formula or calculate both to compare results

Default RPE 10 = set taken to failure

The science behind 1RM

Your one-rep max (1RM) is the maximum weight you can lift for one repetition with good form. Instead of testing it directly— which is risky—you can estimate it from a heavier set in the 1–20 rep range using validated formulas.

This calculator uses the Brzycki and Epley formulas to estimate your 1RM from weight and reps. You then get training zones (strength, power, hypertrophy, endurance) and percentage-based weights so you can program workouts safely and effectively.

Why use a 1RM estimate?

  • Program weights as a percentage of 1RM (e.g. 80% for strength)
  • Track strength progress without testing a true max
  • Choose the right training zone for your goal
  • Safer than testing an actual one-rep max, especially alone

Get personalized guidance

A coach can help you turn your 1RM and training zones into a program that fits your goals and recovery.

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For coaches & studios

Coaches and fitness businesses use our platform to program for clients, track progress, and use tools like 1RM and training zones—all in one place.

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