One-Rep Max Calculator (1RM)
Estimate the most you can lift for one rep, with a training percentage table.
Result
How to use
- 1
Enter the weight you lifted with good form.
- 2
Enter how many reps you completed (1–12 gives the best estimate).
- 3
Use the percentage table to choose weights for your training sets.
Questions
Which formula is used?
Two popular ones: Epley (1RM = weight × (1 + reps ÷ 30)) and Brzycki (1RM = weight × 36 ÷ (37 − reps)). They agree closely below 10 reps; the main result is their average.
Is it safe to test a true 1RM?
Maximal lifts carry injury risk, especially for beginners. Estimating from a set of 3–8 reps is safer. Always use a spotter or safety bars for heavy bench presses and squats.
About this One-Rep Max tool
One-Rep Max Calculator (1RM) — Estimate the most you can lift for one rep, with a training percentage table. It is one of 200 free tools on namasivayam.in, made by software engineer Namasivayam Vadivelan for everyday use in India.
Everything is calculated instantly in your browser: nothing you type or upload is sent to any server, there is no sign-up, and it works on mobile and desktop. Enter the weight you lifted with good form.
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Results are estimates to help you plan. They are not financial, tax or medical advice.