One-Rep Max Calculator
Estimate your 1RM from any lift and see your full percentage table.
Tip: estimates are most accurate at 1–10 reps. High reps reduce accuracy.
Estimated One-Rep Max
based on × · formula
Formula (tap to use)
% of 1RM · training loads
| % | Weight |
|---|---|
🏋️ Barbell plate loading (per side)
Loads total ( bar + / side) · not loadable with standard plates
1RM is at or below the bar weight — nothing to load. Lower the bar weight to see plates.
Estimates only — actual 1RM varies by exercise, fatigue and technique. Warm up, use a spotter, and progress gradually. Not medical advice.
Why you’ll love One-Rep Max Calculator
Instant & free
No signup, no paywall, no limits — One-Rep Max Calculator works the moment the page loads.
Completely private
Everything runs in your browser. Nothing you enter is ever uploaded or stored on a server.
Works on any device
Fully responsive and touch-friendly — use it on your phone, tablet or desktop.
Accurate & clear
Built on the real formulas, with a breakdown you can actually trust.
How to use it
Open it
No download and no login — the tool is ready right at the top of this page.
Use it
Enter your details or start interacting. Everything updates live as you go.
Get your result
Copy, download or share your result in a single tap. That’s it.
Frequently asked questions
One-Rep Max Calculator is 100% free — no signup, no watermarks and no usage limits. It’s one of 200+ free tools we build and give away.
It uses the standard formulas and shows its working, so you can verify every number. For big decisions, treat the result as a reliable estimate.
Completely. One-Rep Max Calculator runs entirely in your browser (client-side). Nothing you type, upload or generate is sent to our servers, so your data never leaves your device.
No. It works instantly in any modern web browser — Chrome, Safari, Edge or Firefox — on desktop and mobile.
Yes. The tool is fully responsive and touch-friendly, so it works great on phones and tablets as well as computers.
Global Maple System — a software & AI studio. We built One-Rep Max Calculator (and 200+ other free tools) to show what we can do. Need something custom built? We’d love to help.
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