Calculate Your Limits
Use the Brzycki formula to estimate your max strength.
Ready to Calculate
Enter your lift details above to generate your strength report.
What is One Rep Max?
A One Rep Max (1RM) is the maximum amount of weight a person can possibly lift for one repetition of an exercise. It is the gold standard for measuring pure strength in exercises like the Squat, Bench Press, and Deadlift.
Why Calculate It?
Knowing your 1RM allows you to program your training effectively. Most strength programs prescribe weights based on a percentage of your 1RM (e.g., "Do 5 sets of 5 reps at 75% of 1RM"). Calculating it prevents you from training too light or too heavy.
Who Is It For?
This tool is essential for Powerlifters, Weightlifters, CrossFit athletes, and anyone serious about strength training. Whether you are a beginner establishing a baseline or an advanced lifter planning a peaking block, knowing your numbers is key.
How It Works
Testing a true 1RM can be dangerous and fatiguing. This calculator uses the Brzycki Formula to estimate your max based on a weight you can lift for reps (e.g., 5 reps). This allows you to gauge your strength safely without pushing to absolute failure.
Frequently Asked Questions
How accurate is this One Rep Max Calculator?
This calculator uses the widely respected Brzycki Formula. While it is one of the most accurate methods for estimating 1RM from sub-maximal efforts (especially under 10 reps), individual results can vary based on lifting experience, muscle fiber composition, and fatigue levels. Always treat this as an estimate.
Can I use this for any exercise?
Yes, but it works best for compound lifts like Squats, Bench Press, and Deadlifts. Isolation exercises (like bicep curls) may not scale as predictably with these formulas due to muscle fatigue setting in differently.
Is it safe to test my true 1RM?
Testing a true 1RM places different stress on the body than regular training. Ensure you have proper form, a spotter, and have warmed up thoroughly. For many, calculating an estimated 1RM using this tool is a safer alternative to testing a max effort lift.