One Rep Max Calculator
Estimate your one repetition maximum (1RM) based on the weight you can lift and the number of repetitions you can perform. Compare different 1RM formulas and find useful training weights.
What Is One Rep Max?
One Rep Max (1RM) is the maximum amount of weight you can theoretically lift for one complete repetition of an exercise with proper technique.
Your 1RM can be estimated from a weight you have already lifted for multiple repetitions. This provides a useful way to track strength and plan resistance-training intensity without necessarily testing a true maximum lift.
How Is One Rep Max Calculated?
This calculator uses several established estimation formulas, including the Epley, Brzycki, and Lombardi formulas.
Because different formulas can produce slightly different estimates, the calculator uses the results of multiple formulas to provide a practical estimated 1RM.
1RM Formula Guide
| Formula | Calculation |
|---|---|
| Epley | Weight × (1 + Reps ÷ 30) |
| Brzycki | Weight × 36 ÷ (37 − Reps) |
| Lombardi | Weight × Reps0.10 |
Important Safety Note
A calculated 1RM is an estimate and may not equal your actual maximum strength. Always use proper lifting technique and appropriate safety equipment when performing resistance exercises.
Beginners should avoid attempting maximal lifts without appropriate supervision and experience.
What Should You Do Next?
Understanding your strength level is only one part of planning an effective fitness routine.
You can also explore your daily calorie and nutrition needs to support your fitness goals.