No, you’re not going nuts — your toenails really do grow much more slowly than your fingernails. According to a study performed at the University of North Carolina, fingernails, on average, grow 3.47 millimeters a month. Toenails, on the other hand (or foot, rather), grow only 1.62 millimeters per month. Why fingernails are a speedier bunch, however, remains something of a mystery.
There are two plausible theories, though. The first has to do with “terminal trauma,” which, despite how it sounds, has nothing to do with taking the airport shuttle. It essentially means that the more you use a digit, the quicker the nail grows: Your body assumes your fingernails are being worn down by the constant use of your fingers — scratching, typing, picking your nose — so it calls for speedier growth to make up the difference. Meanwhile, your toenails are safe and sound in the comfort of your shoes.
The second theory suggests that the rate of nail growth corresponds directly with the amount of blood flowing through the digit. Since your hands are closer to the heart than your feet are, more blood is flowing through your fingers than through your toes. Thus, longer fingernails. These theorists also point out that nails in general grow slower in cold weather, when blood flow would be restricted.
Bottom line, we’re not entirely sure what the real reason is. But we do know that if you’re thinking it’s because you bite your toenails more than you do your fingernails, you might want to have a good long think about your life choices.