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One Rep Max Calculator — Lift Strength Estimate

Estimate your one-rep max from any set

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Features

  • Epley formula
  • 1-12 rep chart
  • Training max
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This tool runs on your device — your files and inputs never go anywhere.

How to Use One Rep Max Calculator

Estimate your one-rep max from any set No signup, and nothing gets uploaded for most use.

  1. 1

    Enter your numbers in the input fields.

  2. 2

    Choose the calculation options or frequency.

  3. 3

    The result updates instantly as you type.

  4. 4

    Review the breakdown, chart, or schedule, and copy the answer.

Why you might like it

  • Nothing to upload — the work happens on your device.
  • Free with no signup, no watermarks, and no daily limits.
  • Works in any modern browser on any device — nothing to install.
  • Usually done in a few seconds, so it doesn't get in your way.
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Frequently Asked Questions

What is a one-rep max?

A one-rep max (1RM) is the maximum weight you can lift for a single repetition. It is the standard benchmark for measuring strength across lifts like the bench press, squat and deadlift.

How accurate is the Epley formula?

The Epley formula predicts 1RM within a few percent for most lifters when reps are below 10–12. It becomes less reliable for very high-rep sets.