Calculators
One Rep Max Calculator
Estimate one-repetition maximum from a submaximal set using Epley and Brzycki formulas, with a percentage table for training loads.
- Runs in your browser
- Nothing uploaded
The tool
Enter your numbers below. Results update as you type, and nothing leaves your browser.
Everything you enter stays on your own machine. Nothing is sent to us or to anyone else, which you can confirm in your browser network tab.
What people use it for
- Programming strength training
- Tracking strength progress
- Setting percentage-based loads
- Coaching
About this tool
What the One Rep Max Calculator does
Your one-rep max (1RM) is the heaviest weight you can lift once with good form. It can be estimated from a heavier set of a few reps with formulas such as Epley and Brzycki, which avoids maximal testing. Training loads are then set as percentages of 1RM.
Formula
- Epley: 1RM = weight × (1 + reps ÷ 30)
- Brzycki: 1RM = weight × 36 ÷ (37 − reps)
- Estimate shown is the average of the two
Worked example
Using the starting values in the calculator above:
| Input | Value |
|---|---|
| Weight lifted | 100 |
| Repetitions completed | 5 |
| Result | Value |
|---|---|
| Estimated one rep max | 114.6 |
| Epley | 116.7 |
| Brzycki | 112.5 |
How to read the result
Estimates are most accurate from sets of 3 to 6 reps taken close to failure with good form.
Use a spotter or safety bars for heavy sets.
General information, not medical advice. Speak to a qualified health professional before making changes to diet, exercise or treatment.
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Questions
Questions about this tool
The things clients actually want to know — costs, timelines, ownership and what happens after launch.
The maximum weight you can lift for one repetition with proper form.
Usually within about 5% for sets under ten reps.
Experienced lifters can, safely; many programmes use estimated values instead.
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