Body Frame Size Calculator

What is body frame size?

Your body frame size describes the size of your skeleton: how thick your bones are and how broad your build is. Two people of the same height can have very different frames. Someone with a large frame has bigger, heavier bones and can carry more weight in a healthy way than someone with a small frame. Frame size is mostly set by your genes and does not change with diet or exercise.

How to measure your wrist

Use a flexible tape measure and wrap it around your wrist just below the wrist bone (the bony bump on the little-finger side), where the wrist is narrowest. Keep the tape snug but not tight. Measure your dominant hand, the one you write with, and take the reading two or three times to make sure it is consistent. If you do not have a tape, wrap a piece of string around your wrist, mark it, and measure the string with a ruler.

How frame size is calculated

This calculator uses the height-to-wrist ratio method, a widely used approach also referenced by the US National Library of Medicine. Your height is divided by your wrist circumference, both in the same units:

r = height ÷ wrist circumference

A smaller ratio means your wrist is thick compared with your height, which points to a larger frame.

Sex	Small frame	Medium frame	Large frame
Men	Above 10.4	9.6 – 10.4	Below 9.6
Women	Above 11.0	10.1 – 11.0	Below 10.1

Examples: A man who is 170 cm tall with a 16.5 cm wrist has a ratio of 10.30, which is a medium frame. A woman who is 160 cm tall with a 14 cm wrist has a ratio of 11.43, which is a small frame.

Frame size by wrist measurement

If you prefer, you can also estimate your frame from your wrist size alone, using this commonly used chart:

Group	Small	Medium	Large
Women under 5 ft 2 in	Under 5.5 in	5.5 – 5.75 in	Over 5.75 in
Women 5 ft 2 in – 5 ft 5 in	Under 6 in	6 – 6.25 in	Over 6.25 in
Women over 5 ft 5 in	Under 6.25 in	6.25 – 6.5 in	Over 6.5 in
Men over 5 ft 5 in	5.5 – 6.5 in	6.5 – 7.5 in	Over 7.5 in

How frame size affects your ideal weight

Most ideal weight formulas assume a medium frame. A common rule of thumb is to subtract about 10% from the ideal weight for a small frame and add about 10% for a large frame. For example, if your ideal weight for a medium frame is 65 kg, it would be around 58.5 kg with a small frame and 71.5 kg with a large frame. Frame size also helps explain why BMI can be misleading: a person with a large frame may have a slightly higher BMI while still being healthy. Check your numbers with our BMI Calculator and Body Fat Calculator.

Limitations

The wrist method is quick and easy, but it is only an estimate. Swelling, a lot of fat or muscle around the wrist, or an old injury can affect the reading. The elbow breadth method, which measures the width of the bone at the elbow with calipers, is sometimes used by professionals as a more accurate alternative.

Frequently Asked Questions

How do I know my body frame size?

Measure your wrist just below the wrist bone and divide your height by your wrist size. For men, a ratio above 10.4 is small, 9.6–10.4 is medium and below 9.6 is large. For women, above 11.0 is small, 10.1–11.0 is medium and below 10.1 is large.

What is a normal wrist size?

Adult wrist sizes usually range from about 14 to 17 cm (5.5–6.75 in) for women and 16 to 19 cm (6.25–7.5 in) for men, depending on height and build.

Can I change my frame size?

No. Frame size depends on your bone structure, which is mostly determined by genetics. Losing or gaining fat or muscle changes your weight and shape, but not your frame.

Does frame size affect ideal weight?

Yes. People with a small frame usually have a lower healthy weight, and people with a large frame a higher one. A common guide is to adjust a medium-frame ideal weight down or up by about 10%.

Which wrist should I measure?

Measure your dominant wrist, the one on the hand you write with, as this is the standard used in most frame size charts.