How accurate is the Epley formula?

It's a well-tested estimate accurate to within a few percent for reps under 10; accuracy decreases for higher rep sets.

One Rep Max Calculator

Estimate the maximum weight you could lift for a single repetition, based on the weight and reps performed on a recent set, using the Epley formula.

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Results

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Formula

1RM = Weight × (1 + Reps / 30)

The Numbers Behind Your Workout: Pace, One-Rep Max, and Heart Rate Zones

How pace, estimated 1RM, and target heart rate zones are calculated, with real training examples.

How the Epley Formula Estimates Your One-Rep Max

The math behind estimating a 1RM from submaximal sets, and why the formula gets less reliable at higher rep counts.

Building Strength: How to Track Progress Without Testing a True Max Every Week

How to use estimated one-rep max and body-weight-relative strength scores to track progress safely over time.

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Steps to Calories Calculator

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