How do I use the One Rep Max Calculator?

Enter the weight you lifted. Enter the number of reps you completed. Choose lbs or kg. Click Calculate 1RM to see your estimated one-rep max. Review the training load chart for percentage-based programming.

Is the One Rep Max Calculator free?

Yes, the One Rep Max Calculator is completely free. It runs entirely in your browser with no signup, no download, and no data sent to any server.

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One Rep Max Calculator

Estimate your one-rep max (1RM) using 7 proven formulas. Get percentage-based training loads for any lift.

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One Rep Max Calculator

Estimate your one-rep max (1RM) for any lift using multiple proven formulas. Get percentage-based training loads.

Weight Lifted

Reps Performed

How to use

How to Use the One Rep Max Calculator

1 Enter the weight you lifted.
2 Enter the number of reps you completed.
3 Choose lbs or kg.
4 Click Calculate 1RM to see your estimated one-rep max.
5 Review the training load chart for percentage-based programming.

The One Rep Max (1RM) is the maximum weight you can lift for a single repetition. This calculator uses 7 proven formulas (Epley, Brzycki, Lander, Lombardi, Mayhew, O'Conner, Wathan) and averages them for the most accurate estimate. The closer to 1 rep you test with, the more accurate the estimate.

The training load chart shows how much weight to use at each percentage of your 1RM. For strength training, use 80-95% (1-5 reps). For hypertrophy (muscle growth), use 65-80% (6-12 reps). For endurance, use 50-65% (15+ reps). Always warm up properly before heavy lifts.

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