One-rep max calculator

Estimate your one-repetition maximum from the weight used and repetitions completed.

Results are planning estimates. Adjust them to your condition and circumstances.

Set details

Weight used (kg)

Repetitions

Enter 1 to 10. Estimates vary by exercise and how the set was performed.

Estimated 1RM

Enter the weight and repetitions.

Percentage	Estimated load

Reference materials

Calculation rule: Applies the Epley equation (weight × (1 + reps/30)) to a load completed for 1–10 repetitions.

Limitations: This is not a measured maximum. Error varies by exercise, technique, training history, and fatigue; do not test it with an unsupervised maximal attempt.

When to stop or seek advice: Stop for chest pressure, unusual breathlessness, dizziness, faintness, or sharp pain and seek appropriate care.

What the references support: The linked paper studied prediction from bench-press repetitions in men. It is not presented as the origin or original validation of the Epley equation.

References checked: 2026-08-05
Responsible publisher: Bookclip Health

Bench-press repetitions prediction study (1995)