ACTIVITY AND TRAINING ESTIMATES
One Rep Max Calculator
Estimate one-repetition maximum strength from a lifted weight and repetitions using the Epley equation.
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Your result
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Enter your values and select Calculate. Your result stays on this device.
How it works
Epley estimate: 1RM = weight × (1 + repetitions ÷ 30).
Assumptions
Best suited to technically consistent submaximal sets. Exercise type, range of motion, fatigue, experience, equipment, and formula choice change the estimate.
About this calculator
This 1RM calculator gives lifters a planning estimate without requiring a true maximal attempt. The Epley method and an 80% reference load are shown explicitly.
How to use it
- Enter the weight used for a technically consistent set.
- Enter completed repetitions from 1 through 30.
- Calculate the Epley one-rep-max estimate.
- Choose real training loads conservatively with qualified coaching and safe equipment.
Use case
one rep max calculator: a clear planning check
Apply the Epley formula to entered weight and repetitions, show an 80% reference, and keep maximal-lifting safety limits explicit.
Estimate a one-repetition maximum from a technically consistent submaximal set.
Source and update
Last reviewed: 2026-08-22
National Strength and Conditioning Association — One-Repetition Maximum TestingFrequently asked questions
What is one-rep max?
It is the greatest load a person can lift once with proper technique for a specific exercise.
Is an estimated 1RM exact?
No. Equations differ and individual performance depends on exercise, experience, fatigue, range of motion, and technique.
Should I test the displayed maximum?
Not automatically. A maximal attempt has risks and should use appropriate preparation, supervision, equipment, and health judgment.
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