About 1RM Pro
We're on a mission to make strength training safer and more scientific for athletes worldwide.
Our Mission
At 1RM Pro, we believe that every athlete deserves access to professional-grade training tools. Our calculator combines decades of sports science research with modern technology to deliver accurate, reliable strength assessments that help you train smarter and safer.
Whether you're a competitive powerlifter, a weekend warrior, or a coach training the next generation of athletes, our tools are designed to help you make data-driven decisions about your training loads and progression.
The Science Behind Our Calculations
Epley Formula (1985)
Developed by Boyd Epley at the University of Nebraska, this formula is widely used in strength and conditioning programs across the world.
1RM = Weight × (1 + Repetitions / 30)Best for: Moderate repetition ranges (5-10 reps)
Brzycki Formula (1993)
Created by Matt Brzycki, this formula is particularly accurate for lower repetition ranges and is commonly used in powerlifting circles.
1RM = Weight × 36 / (37 - Repetitions)Best for: Lower repetition ranges (1-5 reps)
Lombardi Formula (1989)
Developed through regression analysis of competitive weightlifters, this formula uses an exponential relationship between reps and intensity.
1RM = Weight × Reps^0.10Best for: Experienced lifters with consistent technique
Why We Use Multiple Formulas
No single formula is perfect for every individual or situation. By calculating your 1RM using multiple validated formulas and showing you the range, we give you a more complete picture of your strength potential. This approach accounts for individual differences in muscle fiber composition, training experience, and lift-specific factors.
Our Team
1RM Pro was created by a team of strength coaches, sports scientists, and software engineers passionate about making professional training tools accessible to everyone.
Dr. Sarah Mitchell
Sports Science Advisor
Coach Mike Anderson
Strength & Conditioning Expert
Alex Chen
Lead Developer
Ready to Calculate Your 1RM?
Join thousands of athletes using our calculator to optimize their training.