Strength tool

One-Rep Max Calculator: Estimate Your 1RM

Use a completed set to see an estimated one-rep max range from two equations.

Use the toolFree · No account required

Enter a completed set

Use the weight and reps you completed while maintaining good form.

Estimated 1RM

100.5 kg

Epley101.5 kg
Brzycki99.5 kg

Estimated range: 99.5–101.5 kg

What does this result mean?

This number averages the Epley and Brzycki estimates from your set. It is a rough reference for a single repetition of the same exercise, not a measured personal record.

The range only shows the difference between the two equations. Your actual maximum is not guaranteed to fall within it.

The calculation runs in your browser. TrainPact does not receive or store your inputs.

Load table

Approximate loads by percentage

Rounded to 0.5

For example, the 75% row shows 75% of the average estimate: approximately 75 kg.

This percentage does not prescribe a repetition count. Use the table to interpret loads in your program; the 100% row is not a recommendation to attempt a maximum.

%100

100.5 kg

%95

95.5 kg

%90

90.5 kg

%85

85.5 kg

%80

80.5 kg

%75

75 kg

%70

70 kg

%65

65 kg

%60

60 kg

%55

55 kg

%50

50 kg

Why is this an estimate?

Equations can produce different results from the same set. Daily performance, technique, and fatigue also vary. This result does not mean you should attempt a true one-rep maximum.

An easy warm-up set or repetitions with deteriorating technique can be misleading. Do not transfer an estimate from one exercise to another.

Study: predicting 1RM from multiple-repetition sets (new tab)

Plan your training loads

Compare programs when deciding how to structure your strength training.

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Quick guide

From one set to an estimated maximum

One-rep max is a rough reference for the weight you might lift once in the same exercise. The tool runs your set through the Epley and Brzycki equations, then shows the range and average.

How to use it

  1. 1Choose a set completed with good form.
  2. 2Enter the load and 1–12 repetitions.
  3. 3Compare the percentage table with loads in your programme.

How should you read it?

If you enter 80 kg for 8 reps, the equations may be close but that does not mean you should attempt 100 kg today. It gives you a shared scale for discussing training loads.

Keep the limits in view

The result cannot assess technique, fatigue, or injury risk. Do not transfer an estimate from one exercise to another.

What this tool cannot do

Equations cannot assess technique, daily fatigue, or injury risk. The result is not a reason to attempt a true maximum.

Source on 1RM methods

Sources last checked: September 2026