Fitness

One Rep Max Calculator

Estimate one-rep max and percentage loads from weight, reps, and formula.

Updated: May 15, 2026

Input

Estimate one-rep max and percentage loads from weight, reps, and formula.

Output weights use the same unit as your input. Not a direct 1RM test. Higher reps can be less accurate. Prioritize safety when testing maxes or loading workouts.

Result

116.7

1RM (input unit)

100%116.7
95%110.8
90%105
85%99.2
80%93.3
75%87.5
70%81.7
65%75.8
60%70
50%58.3

Use this as a guide and adjust for your real conditions.

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How to use

  1. Enter Weight, Reps, Formula.
  2. Check the estimate in the result area.
  3. Share a reproducible URL if needed.

How to read the result

  • Read 1RM estimate, Percentage loads as quick decision-making estimates.
  • Do not treat the result as a fixed answer; adjust assumptions to see the range when needed.

Useful tips

  • Useful when you want to set strength training loads; adjust inputs to compare scenarios.
  • Useful when you want to estimate max strength from a recent set; adjust inputs to compare scenarios.
  • Use results as training guides and adjust for condition, heat, surface, and fatigue.
  • If the result feels too demanding, reduce distance, intensity, or duration and recalculate.

Calculation

Uses Epley, Brzycki, or Lombardi to estimate 1RM and percentage-based training weights.

Notes

  • Adjust for your condition and environment.
  • This is not medical or coaching advice.
  • Stop exercising if you feel pain or discomfort.

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FAQ

Are inputs saved?

Inputs are calculated in your browser and are not sent to a server. When you use sharing, the reproducible URL includes the current conditions.

Are results exact?

Use results as everyday estimates. For exact decisions, confirm with official or specialized sources.

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