The standard age at which an adult's feet stop growing is a few years after adolescence, or around 21, according to the Maine Senior Guide. However, a few factors may necessitate that an adult wear a larger shoe size later in life.
Pregnant women often need to wear slightly larger shoes during pregnancy because their feet swell. In fact, any significant weight gain during adult life can lead to swelling of the feet. It is possible to regain a previous foot size after significant weight loss as well. Flattening of feet over time may lead to a need for wider shoes.
It is estimated that people over 40 gain half a shoe size every 10 years. The feet absorb shock when walking or running, and they smooth out the impact of landing. Feet also act as levers that propel the body forward. Correct shoe size is important for healthy feet, and shoes should be replaced regularly. Measuring feet regularly, even into adulthood, allows people to buy the correct shoe size for their feet.