Health / Browser calculator

One Rep Max Calculator

One Rep Max Calculator works from the inputs you provide and returns epley one-rep estimate, brzycki one-rep estimate. Use the calculation panel to explore a scenario, then check the formula and limitations before applying the result.

Your inputs

Minimum: 1e-06
Minimum: 1 · Maximum: 10 · Whole numbers

Your results

Enter your values and calculate to see the result.

This calculator is for informational purposes only and is not a substitute for professional medical advice.

Formula and calculation method

Epley estimate = weight × (1 + reps/30). Brzycki estimate = weight × 36/(37−reps). A one-rep set is reported at the lifted weight.

Approximate for sets up to 10 repetitions. Do not use this estimate to attempt an unsafe maximal lift.

How to use one rep max calculator

  1. Set Lifted weight (any consistent unit). The example below uses 80.
  2. Set Completed repetitions. The example below uses 5.
  3. Select Calculate to update the result. Reset restores the illustrated inputs. Copy, print or download your own result if you need a record.

Worked example

Example inputs
Lifted weight (any consistent unit)
80
Completed repetitions
5
Epley one-rep estimate
93.33333333
Brzycki one-rep estimate
90

Factors affecting your result

Approximate for sets up to 10 repetitions. Do not use this estimate to attempt an unsafe maximal lift.

Changing lifted weight (any consistent unit) changes the scenario being evaluated. Adjust one input at a time when comparing results, keep a copy of the assumptions, and compare values using the same unit and period. A precise arithmetic result does not make an uncertain assumption precise.

Frequently asked questions

How does the one rep max calculator work?

Epley estimate = weight × (1 + reps/30). Brzycki estimate = weight × 36/(37−reps). A one-rep set is reported at the lifted weight.

What inputs does One Rep Max Calculator need?

Enter lifted weight (any consistent unit), completed repetitions. Choose values that correspond to the same situation and measurement convention.

How should I interpret the one rep max calculator result?

Approximate for sets up to 10 repetitions. Do not use this estimate to attempt an unsafe maximal lift.

Are my one rep max calculator inputs uploaded?

No. The calculation runs in this browser. Favorites, recent tool names, theme and formatting preferences may be saved locally, but calculation inputs are not sent to a calculation server or stored by this website. Shared links do not include entered values.

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