One Rep Max
Calculator
The most accurate 1RM calculator for serious lifters. Optimize your training intensity for Bench Press, Squat, and Deadlift.
What is a One Rep Max?
Your One Rep Max (1RM) is the theoretical limit of maximum weight you can lift for a single, clean repetition. It serves as the baseline for all percentage-based training, ensuring every set you perform is optimized for your specific goals suitable for powerlifting and bodybuilding.
1RM Calculator
Behind the Math
Epley Formula
1RM = Weight × (1 + Reps/30)
The industry standard for 3-10 rep ranges. It tends to be slightly more optimistic but highly accurate for experienced lifters performing compound movements such as the bench press.
Brzycki Formula
1RM = Weight / (1.0278 - 0.0278 × Reps)
Known for its reliability across wider rep ranges. It can be more conservative as reps increase, often favored for safety-focused estimations in strength training programs.
Train Smarter, Not Harder
Stop guessing. Percentage-based training allows you to target specific physiological adaptations. Use our 1RM calculator to precisely calculate your working sets.
Learn more about 1RM-based PeriodizationCommon Questions
Is this accurate for beginners?
Yes, but technique consistency is key. Beginners might find their 1RM fluctuates rapidly as neural efficiency improves. We recommend re-testing every 4-6 weeks using this one rep max calculator.
Which lifts should I calculate?
Focus on the "Big Three": Squat, Bench Press, and Deadlift. Overhead Press is also a great candidate. Isolation exercises (like curls) are less suitable for 1RM testing.
How often should I test my 1RM?
We recommend testing your One Rep Max every 8-12 weeks. Testing too frequently can drain your Central Nervous System (CNS) and increase injury risk. Use sub-maximal testing in between cycles.
Is 1RM training safe?
1RM testing is generally safe for experienced lifters with good form. Beginners should stick to "technical maxes" or predicted 1RMs using our calculator to avoid injury ensuring safety.