One Rep Max Calculator
Estimate your one rep max (1RM) for any lift. Uses multiple formulas for accuracy and provides training percentages.
One Rep Max Calculator
Estimate your one rep max (1RM) for any lift
Formula
Brzycki: 1RM = weight × (36 / (37 - reps))How to Use This Calculator
- 1
Select your unit
Choose between pounds (lbs) or kilograms (kg).
- 2
Enter the weight lifted
Input the weight you lifted for multiple reps.
- 3
Enter your reps
Input how many repetitions you completed (1-30 reps).
- 4
View your estimated 1RM
See your estimated one rep max using multiple formulas and training percentages.
Frequently Asked Questions
What is a one rep max (1RM)?
Your one rep max is the maximum weight you can lift for a single repetition with proper form. It's used to measure strength and calculate training weights.
How accurate are 1RM calculators?
Calculators are most accurate with 1-10 reps. Higher rep ranges (10+) become less accurate. We use multiple formulas (Brzycki, Epley, Lander) and average them for better accuracy.
How do I use training percentages?
Training percentages help program your workouts. For strength: 85-95% for 1-5 reps. For hypertrophy: 65-80% for 6-12 reps. For endurance: 50-65% for 15+ reps.