One Rep Max Calculator
Estimate the maximum weight you could lift once (1RM) from a lighter set.
Inputs explained
- Weight Lifted (lbs) — The weight you used for the set. Example: 185.
- Number of Reps — How many reps you completed with that weight. Example: 5.
How to use it
- Fill in the fields above — each input has a hint describing exactly what to enter
- Press Calculate to get your result instantly, right on this page
- Copy the result, save the tool to favorites, or share and embed it anywhere
Understanding the result
Example: Lifting 185 lbs for 5 reps estimates a 1RM of about 208 lbs.
Frequently asked questions
Is the One Rep Max Calculator free to use? Yes — it is completely free, with no sign-up, no download and no usage limits. You can use it as often as you need.
Is my data private? Yes. The calculation runs entirely in your browser — the values you enter are never sent to our servers, stored or shared with anyone.
What information do I need? Just the following: Weight Lifted (lbs), Number of Reps. Each field includes a hint explaining exactly what to enter.
Can I use it on my phone? Yes — the tool is fully responsive and works on any device, and the same calculator is available in the EasyWorkCalcs mobile app.
Privacy
Everything you enter into the One Rep Max Calculator is processed entirely in your browser. Nothing is uploaded, stored or shared — your data stays on your device.