One Rep Max Calculator - Calculator See


One Rep Max Calculator

Calculate your estimated one-rep maximum (1RM) for strength lifts using the Brzycki, Epley, and Lombardi formulas from any submaximal set.

Calculator Inputs

lbs
Weight completed in a submaximal set.
reps
Most accurate between 1 and 10 reps.
Powerlifting standard equations.

Calculated Results

Estimated One-Rep Max (1RM)
225 lbs (102.1 kg)
90% of 1RM (3-4 Reps) 202.5 lbs
80% of 1RM (7-8 Reps) 180.0 lbs
70% of 1RM (11-12 Reps) 157.5 lbs
Values calculate live as you adjust inputs.

About One Rep Max Calculator

A One Rep Max (1RM) calculator assesses maximal strength capabilities by extrapolating the heaviest single repetition you can perform on exercises like the squat, bench press, or deadlift without testing to complete nervous exhaustion.

What is One Rep Max Calculator?

A One Rep Max (1RM) calculator assesses maximal strength capabilities by extrapolating the heaviest single repetition you can perform on exercises like the squat, bench press, or deadlift without testing to complete nervous exhaustion.

How to Use This Calculator

  1. Enter the barbell weight completed for a high-effort set.
  2. Specify the exact number of clean reps executed.
  3. Review your theoretical single-rep limit alongside training percentage blocks (70%, 80%, 90%).

The Mathematical Formula & Variables

Epley: 1RM = Weight * (1 + Reps/30); Brzycki: 1RM = Weight * (36 / (37 - Reps))

Variables Definition

Symbol / Variable Name Description
W Load Weight lifted during test set.
r Reps Valid repetitions completed prior to failure.

Step-by-Step Worked Example

Scenario: Bench pressed 195 lbs for 5 clean repetitions.

  1. Epley: 195 * (1 + 5/30) = 195 * 1.1667 = 227.5 lbs.
  2. Brzycki: 195 * (36 / (37 - 5)) = 195 * (36/32) = 195 * 1.125 = 219.4 lbs.
  3. Average estimated 1RM = 223.5 lbs.

Result: Estimated 1RM = 225 lbs

Frequently Asked Questions

How many reps should I test for maximum accuracy?

Formulas are most accurate when using weights that cause failure between 3 and 6 repetitions. Testing with sets over 10 repetitions introduces muscular endurance factors that degrade prediction accuracy.