05 / 07 Free fitness calculator

One-Rep Max
Calculator

Estimate the heaviest weight you can lift once from a recent working set.

Enter your details
kg
The load used for your completed set.
reps
Completed reps with consistent technique.

● Calculations happen on your device. Nothing is uploaded.

Result05

Enter your details above. Your result will appear here and be saved privately in this browser.

Understand your result

What each number
actually means.

The estimate averages the Epley and Brzycki equations. Sets of 1–10 consistent reps are most useful.

01

Estimated 1RM

A calculated maximum based on a submaximal set, useful when a true maximal attempt is unnecessary.

02

Training percentages

90%, 80%, and 70% turn the estimate into practical strength and volume targets.

03

Good input set

Use a recent set with stable technique and no more than 10–12 repetitions.

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Your latest
calculations.

Stored locally on this device. Clear it whenever you want.

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Good to know

A useful estimate.
Not a diagnosis.

Use the result as a planning baseline, track your real-world response, and adjust over time. Individual needs can vary.