About Our One Rep Max Calculator
Your trusted tool for calculating one-rep max estimates using scientifically validated formulas.
Our one rep max calculator is built to help lifters accurately estimate their maximum strength without risking injury. Instead of testing a true one-rep lift, you can simply enter the weight lifted and reps performed to calculate your estimated 1RM (e1RM) instantly.
This tool is designed for strength training, powerlifting, bodybuilding, and CrossFit athletes who want reliable numbers for programming. Whether you're calculating a squat 1RM, bench press max, or deadlift one rep max, our calculator delivers fast and practical results.
We use proven 1 rep max equations and rep max conversion formulas trusted by coaches and athletes worldwide. Along with your one rep max, you'll also get percentage values, rep ranges, and max rep estimates to plan workouts, warm-up sets, and progressive overload.
Our goal is simple: provide a free, accurate, and easy-to-use strength calculator that helps you train smarter, track PRs, and improve performance safely—no guesswork, no unnecessary complexity.
Our Mission
We created this calculator to help strength athletes, powerlifters, weightlifters, and fitness enthusiasts train smarter and safer. By providing accurate 1RM estimates, we enable you to design effective training programs without the risks associated with frequent maximum lift attempts.
Why Calculate Your 1RM?
Knowing your one-rep max is essential for:
- Designing periodized training programs
- Tracking strength progress over time
- Setting appropriate training percentages
- Competing in powerlifting meets
- Avoiding unnecessary injury risk from frequent max attempts
The Science Behind It
Our calculator uses two of the most widely validated formulas in strength training:
Brzycki Formula (1993)
Developed by Matt Brzycki, this formula is most accurate for lower rep ranges (1-8 reps). It's the preferred method for powerlifters and strength athletes who typically work in lower rep ranges.
Epley Formula (1985)
The Epley formula works better for higher rep ranges (10+) and is commonly used by bodybuilders and general fitness enthusiasts. It tends to give slightly more conservative estimates.
Free & Privacy-Focused
This calculator is completely free to use and requires no registration. We don't store your calculations or personal data. All calculations happen in your browser for maximum privacy and speed.
Feedback & Support
We're constantly working to improve this tool. If you have suggestions, find bugs, or need help using the calculator, please don't hesitate to reach out through our contact channels.