One Rep Max (1RM) Calculator

Use this free one rep max calculator to estimate your 1RM from any working set using Epley or Brzycki.
Your Lift

Enter Your Lift

Input weight and reps to estimate your 1RM

About 1RM Estimation

The Epley formula is the most commonly used 1RM estimator: 1RM = weight × (1 + reps/30). These formulas are most accurate for 1-10 reps. Beyond 10 reps, accuracy decreases due to endurance factors.

Always warm up properly and use a spotter when attempting a true 1RM. The estimated value is a safe starting point for programming.

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How our one rep max calculator works

1

Enter weight and reps

Type the weight you lifted and the number of clean reps you completed. Best results come from sets of 1-10 reps.

2

We estimate your 1RM

Using Epley, Brzycki, Lombardi, and OConner formulas, we compute an estimated 1RM. The calculator shows all four estimates so you can pick the most conservative.

3

See your training percentages

Get a chart of 50-100% 1RM weights for hypertrophy (65-75%), strength (80-90%), and power (85-95%) training zones.

Key things to know about our one rep max calculator:

  • Dont test your true 1RM often: Maxing out is fatiguing and injury-prone. Use submaximal sets (3-5 reps) and the 1RM calculator to estimate progress.
  • Beginners benefit more: Strength gains in year 1 are mostly neural. After that, the 1RM grows about 5-10 lbs per month for upper body lifts with consistent training.
  • Lift-specific formulas: Lower body lifts (squat, deadlift) often have higher estimated 1RMs from formulas than upper body (bench, overhead). Use judgment per lift.

For related calculations, try our BMI calculator.