One Rep Max Calculator
Estimate your 1-rep max from any rep count (Epley formula)
Use this when you need a fast, accurate result — no sign-up, works entirely in your browser.
Estimated 1RM—
80% (8 reps)—
70% (12 reps)—
90% (3 reps)—
How to Use
- Enter your details into the fields above.
- Click the calculate button to get your result instantly.
- Use the clear button to start a new calculation.
Example
- Lift 80 kg for 5 reps → Estimated 1RM ≈ 93.3 kg; 80% (8 reps) ≈ 74.7 kg, 90% (3 reps) ≈ 84 kg
- 100 kg × 5 reps → Estimated 1RM ≈ 116.7 kg (90% ≈ 105 kg, 80% ≈ 93.3 kg)
Formula
Epley's formula: 1RM = weight × (1 + reps ÷ 30). Useful for programming training loads as percentages of your 1RM.
About One Rep Max Calculator
Estimate your 1-rep max from any rep count (Epley formula). This free online tool gives you fast, accurate results without registration or downloads.
Everything runs locally in your browser, so your data is never uploaded or stored — privacy first.
Frequently Asked Questions
Is this tool free to use? +
Yes, it is completely free with no registration or download required.
Is my data private? +
Yes. Everything is processed locally in your browser. Nothing is uploaded or stored on our servers.
Does it work on mobile? +
Yes, it works on any device — phone, tablet, or desktop.