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Calculate your 1RM!

Calculate your 1RM (One Rep Max)





*It is always an estimate

Explanation of the 1RM Calculator

The 1RM (One Rep Max) calculator uses the Epley formula to estimate the maximum weight you can lift once (1RM) based on the weight you can lift for a given number of reps.

Epley formula:
=weight×(1+0.0333×repetitions)

For example, if you can lift 100 kg 5 times, your estimated 1RM is:
=100×(1+0.0333×5)=116.65kg

This formula is general and is often used for compound exercises such as squats, deadlifts and bench presses. However, not all exercises are created equal and some isolation exercises, such as bicep curls or triceps pushdowns, may have different strength profiles. That's why we introduced adjustment factors for each exercise:

  • Squat, Bench, Deadlift: No adjustment, factor is 1.

  • Shoulder Press: 0.95, because it is generally slightly less stressful than the large compound exercises.

  • Bicep Curl: 0.85, because it is an isolation exercise and the muscle group is smaller.

  • Tricep Push Down: 0.9, also an isolation exercise, but slightly more taxing than a bicep curl.

These adjustment factors are general estimates and may vary depending on the source or specific population. They are intended to provide a more accurate 1RM estimate for each specific exercise.

Why use a 1RM calculator?

Determining your one-repetition maximum (1RM) is an essential benchmark for strength athletes, bodybuilders and athletes. The 1RM represents the maximum weight a person can lift once for a given exercise. Although you can test it immediately by lifting heavier and heavier until you reach your maximum, this can be risky and increase the risk of injury. This is where the 1RM calculator comes into play.

1. Safety: Testing your 1RM directly can be risky, especially without the proper warm-up procedure or guidance. A 1RM calculator can give you an estimated 1RM based on lighter weights and more reps, eliminating the risk of working with too heavy weights that could potentially cause an injury.

2. Convenience: Instead of spending time building and testing your maximum possible weight for an exercise, a 1RM calculator allows you to get an estimate quickly and easily. This saves time and energy that you can put back into your training.

3. Periodization and programming: For those who follow training plans or create their own, it is useful to know your estimated 1RM. This helps determine training intensities for different cycles or weeks, and ensures systematic progression in your strength training.

4. Motivation: By regularly estimating and tracking your 1RM, you can monitor your progress. This can be motivating and encourage you to adjust your training schedules and efforts to continuously improve.

5. Comparison: If you participate in competitive strength sports, it can be helpful to know your 1RM so you can compare your performance with others in your weight class or age group.

In summary, a 1RM calculator offers a safe, fast and efficient way to gain insight into your strength level. It allows you to customize your training, track your progress and pursue your sporting goals.