Does fWHR change with age?

Through adolescence the face grows in height as well as width, and the lower face is among the last parts to finish, often into the late teens or early twenties. Puberty adds sex-typical growth, covered in does testosterone make your jaw bigger. So an fWHR taken at fifteen is a snapshot of a face that has not finished. Comparing it with an adult's, or with a research average from adults, does not mean much.

Once growth ends, the zygomatic bones that set width and the maxilla that sets midface height are structural. What changes the measured ratio is what sits over them.

• Body fat. The largest effect. Fat over the cheekbones adds width, so the ratio rises with weight gain and falls with weight loss.
• Brows and eyelids. The height leg starts at the brow or eyelid. Brows that sit lower, or upper-lid skin that folds more with age, shorten it and push the ratio up.
• Lips. The height leg ends at the upper lip, which tends to thin and lengthen with age; see can your philtrum get longer.
• The photo. A close lens narrows the outer face; tipping the chin changes the height. These swings can be larger than years of ageing.

Use the same tool and the same photo setup each time: eye level, arm's length or further, head level, neutral expression. The free fWHR calculator shows whether width or height drives the result, which tells you whether a change came from the cheeks or the brow. And remember there is no target to chase: what is a good fWHR explains why a typical ratio is simply part of an average face.