1RM Calculator

Estimate your one-rep max from any weight and rep count using the Epley formula — updated instantly as you type.

Tool Introduction

Your one-rep max (1RM) is the heaviest weight you can lift for a single repetition with proper form. This calculator estimates 1RM from a submaximal set using the Epley formula — a widely used method in strength training. Use the percentage table to plan working sets for hypertrophy, strength, or power programs. Results are estimates; always use a spotter when testing true maxes.

Calculate

Enter a positive number for the weight you lifted.

Enter a positive whole number from 1 to 30.

Estimated 1RM (Epley)

—

Enter weight and reps to calculate.

Training percentage table
% Weight Load Typical use
Results will appear here.

How to Use

  1. Enter the weight you lifted and select kg or lb.
  2. Enter how many reps you completed (1–30).
  3. Your estimated 1RM and percentage table update automatically.
  4. Click Calculate to refresh, Copy to save the report, or Clear to reset.

Formula: 1RM = weight × (1 + reps ÷ 30). Best accuracy with 2–10 reps.