One Rep Max Calculator
Estimate one-repetition maximum from the weight and reps you can lift (Epley, Brzycki, Lombardi).
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Result
Formula
Epley: w × (1 + r/30). Brzycki: w × 36 ÷ (37 − r).
About this calculator
Estimate your one-repetition maximum (1RM) for a given lift based on the weight and number of repetitions you can perform, using validated prediction formulas. The calculator uses several established 1RM prediction formulas that estimate the maximum weight you can lift for one repetition based on a submaximal effort (weight and reps).
How to use
- 1
Lift a challenging weight for a set.
- 2
Enter weight and reps.
- 3
Read your estimated 1RM.
Frequently asked questions
What is a one-rep max (1RM)?
Your one-rep max is the maximum weight you can lift for a single repetition with proper form. It is a common measure of maximal strength.
Why are there multiple formulas?
Different formulas were developed from different studies and populations. Using several provides a range and an average, which can be more reliable than any single formula.
Can I use this for any exercise?
The formulas are most accurate for major compound lifts like bench press, squat, and deadlift. For isolation exercises, predictions may be less accurate.
Please note: Results are estimates for general information only and are not professional or medical/financial advice.