Body Frame Size Calculator
Find out whether you have a small, medium, or large bone structure using your height and wrist circumference.
Enter your height and wrist circumference to see your result.
*Estimate only, based on the height-to-wrist ratio method. Not medical advice.
Want to see your ideal weight range for your frame?
BMI & BMR Calculator🦴 Understanding Body Frame Size
Your skeletal frame is one of the few body measurements that stays constant throughout adulthood.
How it Works
This calculator compares your total height to your wrist circumference. A higher ratio means a relatively thin wrist for your height, which points to a smaller bone structure.
The Formula
Ratio = Height (in) / Wrist (in). Women: ratio > 10.9 small, 9.9-10.9 medium, < 9.9 large. Men: ratio > 10.4 small, 9.6-10.4 medium, < 9.6 large.
Pro Tip
Frame size is most useful as context for interpreting BMI or "ideal weight" charts — a large-framed person can carry more healthy weight than a small-framed person of the same height.
Frequently Asked Questions
What is body frame size and why does it matter? +
Body frame size refers to your skeletal structure - small, medium, or large - based on bone width and density rather than muscle or fat. It matters because ideal weight ranges and BMI interpretation can shift depending on frame size; two people at the same height can have very different healthy weight ranges if their bone structures differ.
How do I measure my wrist circumference correctly? +
Wrap a flexible tape measure snugly (but not tight) around your wrist, just below the wrist bone where your hand meets your arm. Measure in inches for this calculator. Take the measurement two or three times and use the average for the most reliable result.
Why does this calculator ask for gender? +
The height-to-wrist ratio thresholds used to classify frame size differ slightly between men and women because average bone density and skeletal proportions differ by sex. Using the correct thresholds gives a more accurate classification.
Is this the same as the Grant table method? +
This calculator uses the widely cited height-to-wrist ratio method, which is a simplified alternative to older elbow-breadth (Frisancho / Grant) tables that require calipers. Both approaches are estimates and can disagree slightly, especially for people near a category boundary.
Does frame size change over time? +
No. Frame size is determined by skeletal structure, which is essentially fixed in adulthood. It does not change with weight gain, weight loss, or muscle gain, unlike body fat percentage or BMI, which fluctuate with lifestyle.