Standard head sizes are measured with a measuring tape. A measuring tape is the only material that is needed to do this. Start out by placing the measuring tape around the head.
Gender, age and height are factors to consider when measuring the head. When placing the measuring tape around the head, it has to be a little bit above the ears. The average head size for adult men is about 23 inches and the average head size for women is around 22 inches. Head sizes may vary depending on the individual.
To measure the size of the head for hat/headwear fitting or other purposes, wrap a measuring tape around the most extensive piece of the scalp. Make sure it is over the hair, brow, ears and around the back. Make sure that the measuring tape is cozy and comfortable. The measuring tape should not be too tight. If it is comfortable, then the measurements should be accurate. A good tip for getting the best measurement possible is to start from the crown to the base of the ear. When measuring the head, it is also helpful to use a size chart of typical sizes to see what measurement should be expected.