1RM Calculator

Estimate your one-rep max using the Epley formula: 1RM = weight × (1 + reps / 30).

How to use it

  1. Enter the weight you lifted (kg or lb).
  2. Enter the number of clean reps you completed.
  3. Your estimated 1RM and a percentage breakdown (95%, 90%, 85%, 80%, 75%, 70%, 65%, 60%) will update instantly.

What is a 1RM?

Your one-rep max (1RM) is the maximum weight you can lift for a single repetition of a given exercise. Training percentages are usually programmed against this number. Most lifters never test their true 1RM — they estimate it from sets of 3–10 reps using formulas like Epley or Brzycki.