What do fingernails and hair have in common? They’re both made up of the protein keratin and they both grow. Unless you’re a balding man, then you know all too well that hair can stop growing. But what about fingernails? Josh Clark from BrainStuff by HowStuffWorks helps answer a question we’ve all wondered about at least once: How long could our fingernails actually grow if we stopped cutting them?

And the answer is... in the Guinness Book of World Records. Christine “The Dutchess” Watson is a talented singer and performer. She holds the current Guinness World Record for the Longest Fingernails at 10 feet, 2 inches on her left hand and 9 feet, 7 inches on her right hand — a total of 19 feet, 9 inches. Although Watson is Guinness’s official record holder, the former record holder, Shridhar Chillal, still has the world’s longest fingernails, with the ones on his left measuring around 30 feet long.

So, according to Josh here, fingernails can grow to at least 30 feet, but this is not recommended, since Chillal ended up suffering nerve damage in his left arm, which subsequently led to complete loss of function in his left hand and deafness in his left ear.

According to the American Academy of Dermatology, fingernails do grow slowly, but not as slow as toenails. While it takes the average person half a year to grow a fingernail back if they lose it to injury, it takes around a year and a half to grow back a toenail. One of the most interesting facts about fingernails is that the time of year and the time of the day could impact how fast they grow. For example, fingernails tend to grow faster during the day and during summer.