Enter any weight and rep count to instantly calculate your estimated one rep max — using the most trusted formulas in strength training.
Use these weights for different training zones based on your 1RM.
| % of 1RM | Training zone | Reps | Weight |
|---|
Your one rep max (1RM) is the maximum amount of weight you can lift for a single repetition of an exercise. It's the gold standard for measuring absolute strength in movements like the squat, bench press, and deadlift.
Testing your true 1RM requires pushing to complete failure which carries injury risk — especially for beginners. That's why estimated 1RM calculators like this one are so useful. By lifting a weight you can handle for multiple reps, you can safely estimate your maximum without ever attempting it.
No formula is perfect for everyone, but research generally shows the Epley and Brzycki formulas are the most reliable across a wide range of lifters. Both tend to be most accurate when using a weight you can lift for 3–10 reps. Beyond 10 reps, accuracy drops off for most formulas.
Once you know your estimated 1RM, you can use it to structure your training. Strength work is typically done at 85–95% of 1RM for low reps. Hypertrophy (muscle building) is usually 65–80% for moderate reps. The percentage table above gives you these numbers automatically.
These formulas were originally developed for barbell lifts like the squat, bench press, and deadlift. They can be applied to other exercises but are generally less accurate for machine exercises, isolation movements, or anything with a very short range of motion.
Log your workouts, build routines, and track your strength progress over time — all in one place.