One-Rep Max Calculator
Fill in the values and the answer updates as you type.
How the One-Rep Max Calculator works
Epley: 1RM = w × (1 + reps ÷ 30). Brzycki: 1RM = w × 36 ÷ (37 − reps). Estimates are least accurate above 10 reps.
Inputs and results
The One-Rep Max Calculator takes 2 inputs and gives 2 results.
What you enter
- Weight lifted (kg) — starts at 80.
- Reps completed — starts at 8.
What you get
- Estimated 1RM (Epley)
- Estimated 1RM (Brzycki)
Example: One-Rep Max Calculator with the starting values
With weight lifted 80 kg and reps completed 8, the calculator returns:
| Estimated 1RM (Epley) | 101.3 |
|---|---|
| Estimated 1RM (Brzycki) | 99.3 |
Change any value above and the results update straight away.
One-Rep Max Calculator FAQ
How do I use the One-Rep Max Calculator?
Enter weight lifted and reps completed in the fields, then read estimated 1rm (epley) and estimated 1rm (brzycki) in the result panel. The answer updates as you type, and you can press Calculate or Enter to refresh it. Use “Copy link” to share your exact numbers with someone else.
What does the One-Rep Max Calculator calculate?
Estimate your maximum single lift from a multi-rep set. It returns estimated 1rm (epley) and estimated 1rm (brzycki) from the 2 values you provide.
What values does the One-Rep Max Calculator start with?
It opens with weight lifted 80 kg and reps completed 8 so you can see a working result straight away. Replace them with your own numbers, or press Reset to return to these starting values.
Is the One-Rep Max Calculator free and private?
Yes. It is free, needs no account, and runs in your browser, so nothing you type is sent to or stored on our servers. See the Privacy Policy for details.
Can I rely on the One-Rep Max Calculator for medical or health decisions?
Treat the result as a well-rounded estimate. Real situations often have details a general calculator cannot know, so confirm medical or health decisions with a qualified professional. See the Disclaimer for more.