Estimate your maximum lift using proven formulas. Calculate training percentages for bench press, squat, deadlift, and any barbell exercise.
For best accuracy, use a weight you can lift for 1-10 reps
Knowing your 1RM is just the beginning. Track your body composition alongside your strength gains to see the full picture of your fitness progress.
Track Your Body CompositionYour one rep max (1RM) is the maximum amount of weight you can lift for a single repetition with proper form. It's considered the gold standard for measuring maximal strength and is fundamental to programming effective resistance training.
Rather than testing your actual 1RM (which requires careful preparation, spotters, and carries injury risk), most lifters use mathematical formulas to estimate their 1RM based on submaximal lifts. This is safer and provides sufficiently accurate results for training purposes.
Our calculator uses three well-researched formulas:
1RM = weight × (1 + 0.0333 × reps)
Developed by Boyd Epley, this formula is widely used in strength and conditioning. Research published in the Journal of Strength and Conditioning Research found it to be highly accurate for trained individuals, particularly for sets of 10 reps or fewer.
1RM = weight × (36 / (37 - reps))
Created by Matt Brzycki, this formula tends to give slightly more conservative estimates than Epley, especially at higher rep ranges. It's particularly popular in powerlifting communities.
1RM = (100 × weight) / (101.3 - 2.67123 × reps)
The Lander formula provides a middle ground between Epley and Brzycki estimates and is often used as a validation check.
Once you know your 1RM, you can use percentages to program your training effectively:
While 1RM calculators are useful tools, they have limitations:
For most training purposes, calculated 1RMs provide sufficient accuracy. If you need to know your exact 1RM (for competition, for example), work with a qualified coach to test safely.
Strength is just one piece of the puzzle. Track your body fat percentage alongside your lifts to understand how your body composition is changing with your training.
A one rep max (1RM) is the maximum amount of weight you can lift for a single repetition with proper form. It's the gold standard for measuring strength and is used to program training percentages.
1RM calculators are most accurate when using weights you can lift for 1-10 reps. The Epley and Brzycki formulas typically provide estimates within 5% of actual 1RM for trained lifters.
The Epley formula is generally most accurate for 1-10 reps, while Brzycki works well for 1-12 reps. Our calculator averages all three formulas for the most reliable estimate.
Testing actual 1RM carries injury risk and requires proper preparation. For most training purposes, a calculated 1RM from a 3-5 rep set is safer and sufficiently accurate.
Recalculate every 4-8 weeks or after completing a training cycle. This ensures your training percentages stay relevant as you get stronger.
1RM calculators work best for compound barbell movements like squat, bench press, deadlift, and overhead press. They're less reliable for isolation or machine exercises.
Strength numbers tell part of the story. Add body composition tracking to see how your training is transforming your physique.
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