If you've never had short hair, you might wonder whether it would would look good on you. Here's an easy way to figure it out: the 2.25 inch rule.
According to Elle, this measurement was discovered by hair expert John Frieda, who studied faces and found that the angle of the jawbone determines if someone would look better with short or long hair.
To take the test, hold a pencil horizontally under your chin and a ruler under your ear vertically. Measure the distance from your ear to the pencil. If it's less than 2.25 inches (5.7cm), short hair should look great on you. Over 2.25 inches, a longer cut might be more flattering.
Face shape plays into this too and the type of hairstyle that would be most flattering, but the ruler test is a quick and easy way to stop wondering about short locks.