One Rep Max (1RM) Calculator

Estimate your maximum lifting weight for bench press, squat, and deadlift

Testing your true one-rep max can be dangerous without a spotter. This calculator estimates your 1RM based on a weight you can lift for multiple repetitions.

Calculator Inputs

Weight Lifted*

lbs or kg (result matches input)

Repetitions*

Max reps performed (1-10 is best)

Formula*

Results

Enter values above to see your results

Rep-max formulas are most reliable for sets of 2 to 6 reps and drift by 5% or more above about 10 reps; they also differ between lifts and lifters. Treat the estimate as a planning number and do not attempt a true maximal single based on it without proper warm-up, spotting, and experience.

How It Works

We use proven formulas (Epley, Brzycki, etc.) that analyze the relationship between weight lifted and reps performed to project your max strength.

Tips & Best Practices

•Estimates are most accurate for rep ranges between 3 and 10.
•Above 10 reps, fatigue becomes a bigger factor than raw strength.
•Use this to calculate percentages for your training program (e.g., 5 sets of 5 at 75% 1RM).

Frequently Asked Questions

Is this accurate for all exercises?

It is most accurate for compound lifts like Bench Press, Squat, and Deadlift. It is less accurate for isolation movements like curls.

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