Fingernail grows four times faster than toenails.

Fingernails do grow faster than toenails, but the claim of 'four times faster' is incorrect. The actual ratio is approximately 2-3 times faster. Fingernails grow at about 3.47 millimeters per month on average, while toenails grow at about 1.62 millimeters per month. The difference in growth rates is due to better blood circulation and more frequent trauma/injury to fingernails which stimulates growth.