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One Rep Max Calculator

Estimate your one-rep max from any set

100% private. Your files and inputs never leave your device — everything runs locally in your browser.

Features

  • Epley formula
  • 1-12 rep chart
  • Training max
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How to Use One Rep Max Calculator

Estimate your one-rep max from any set. No signup, no uploads, no watermarks.

  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 choose One Rep Max Calculator?

  • No uploads — your files never leave your device.
  • Free forever with no signup, no watermarks, and no limits.
  • Works on any device with a modern browser — no installs.
  • Fast, private, and built for getting the job done in seconds.
Try 1RM for free

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.