Body Frame Size Calculator

The body build calculator classifies your body type into one of three categories - small, medium or large - based on the structure of your skeleton. As the size and density of the skeleton can vary even within the same height range, which can have a significant effect on weight, it is an important factor in understanding healthy weight ranges.

This calculator offers two common measurement methods. The wrist circumference method divides your height by the circumference of your wrist. The elbow breadth method takes into account your height and gender to compare it with a reference range and your elbow breadth.

What is skeleton size and why does it matter?

Skeletal size is a measure of the relative size of your skeleton. It's mostly determined by genetics and doesn't change much with weight gain or loss, making it a stable physical trait that isn't used to assess fitness.

Skeletal size is important because it affects the appropriate range for a healthy weight. People with larger skeletons tend to weigh more than people with smaller skeletons, even when they are the same height, but this does not mean that either of them is unhealthy. Knowing your skeletal size can help you interpret weight and body mass index data in context.

Method with wrist circumference

The wrist is a good place to measure because it's mostly bone and has little fat or muscle which reduces the chance of error in the measurement. You measure the circumference of the narrowest part of your wrist, below the bones at the base of your hand, then divide your height by that wrist circumference.

A higher value indicates that the wrist is slim relative to height, which generally means a smaller skeleton. The reference values are different for women and men.

For example, a man with a height of 175 cm and a wrist circumference of 17 cm has a ratio of approximately 10.3, calculated as 175 divided by 17. As this result falls between 9.6 and 10.4, it corresponds to an average-sized skeleton.

The elbow-width method.

Elbow breadth is the horizontal distance between the two bones of the elbow. The arm is bent at a right angle and fingers are pointed upwards before measuring the widest part of the elbow. This result is then compared to a range for average-sized skeletons based on height and gender. A value below this range indicates a small skeleton, within the range an average-sized skeleton, and above the range a large skeleton.

In some materials this concept is expressed as a skeletal index, with the measurement results standardized for body size.

The width of the elbow for a medium-sized stature, based on standardized reference tables and depending on height is as follows:

A simple test with your index and thumb fingers.

If you don't have a tape measure, use your thumb and index finger to encircle the opposite hand's wrist. If they overlap, it is small build; if they just touch, it is medium build; if they do not reach around, it is large build. This is only a rough estimate and should not replace an actual measurement.

How accurate is this method?

The estimate of height is only a rough guide and not an accurate measurement. The method for determining the wrist circumference and the method for measuring elbow breadth can be subject to error at extremes. In one study, the concordance rate between classification by height, wrist circumference, and elbow breadth was less than 50%. In particular, the method of measuring elbow breadth is generally considered more reliable than the other two methods in men. If results are obtained at extremes, it is usually best to assume a medium build and not focus on precise categorization but rather consider the overall picture.

This tool is for general educational purposes only and does not constitute medical advice. Height is just one small factor in controlling weight and body composition. If you would like information on maintaining a healthy weight please consult with a qualified physician.