About One Rep Max (1RM) Calculator
Estimate your one-repetition maximum (1RM) across seven recognized clinical strength formulas (Brzycki, Epley, Lander, Lombardi, Mayhew, O'Conner, and Wathan). Generates a complete percentage training load table (50% to 95%) with recommended rep targets.
Key Capabilities & Features
- Multi-formula strength comparison: Brzycki, Epley, Lander, Lombardi, Mayhew, O'Conner, and Wathan
- Consensus average 1RM score balancing non-linear and linear models
- Percentage load table (50% to 95%) with specific rep ranges and training adaptations (power, hypertrophy, endurance)
- Metric (kg) and imperial (lbs) weight inputs
How to Use One Rep Max (1RM) Calculator
Enter Lifted Weight
Input the weight lifted on a submaximal set in kg or lbs.
Enter Completed Reps
Input the number of clean repetitions completed to fatigue (1 to 10 reps optimal).
Inspect 1RM & Percentages
Review estimated 1RM consensus and target workout loads for upcoming strength blocks.
Privacy & In-Browser Execution Guarantee
100% client-side calculation. Your data never leaves your browser.
Frequently Asked Questions
Which 1RM formula is most accurate?
The Brzycki and Epley equations are the most validated in exercise science literature for sets under 10 repetitions.
Why estimate 1RM instead of testing true 1RM?
Submaximal estimation dramatically reduces injury risk to joints, ligaments, and the central nervous system compared to testing maximal singles to failure.