How Long Can Human Fingernails Grow?

How do you like to wear your fingernails? Whether you prefer them elongated, clipped to the quick or occasionally chewed, you may have wondered how long they would grow if you left them alone. And by "left alone," we mean for a really, really long time.

As our Brainstuff video host Josh Clark explains in the video above, discovering the lengths to which fingernails can grow is an inexact science bolstered only by those who have spent years grooming their fingernails into winding, coiling lengths.

First, though, let's take a closer look at how fingernails work. Each fingernail is made of keratin, a strong substance that also comprises hair. A fingernail has five parts:

• Nail plate: the visible part of the fingernail, commonly what we refer to as the fingernail

• Nail folds: the skin on each side of the nail plate

• Cuticle: a protective layer of tissue at the bottom of the fingernail that covers new cells as they grow

• Nail bed: the tissue beneath the nail plate, rich in blood vessels and stem cells that help produce new cells

• Lunula: a crescent-shaped section of the nail bed

So how long can fingernails grow? The average person's fingernail grows about three millimeters a month, which is about one-tenth of an inch. It would take two-and-a-half years to grow your fingernails to one full inch beyond the tip of your finger — if you could manage not to break them, that is.

There are a few people who have made a name for themselves by growing ultra-long fingernails; our friends at the Guinness Book of World Records have identified a number of world record holders for "longest fingernails."

Christine "The Dutchess" Walton stopped trimming her nails in 1990 when she was 23 years old. By 2013, the cumulative measurement of all the fingernails on her left hand was more than 23 feet, 11 inches (7.3 meters) in length.

As impressive as this is, she still has some competition. According to Guinness, Shridhar Chillal has been growing out the fingernails on his left hand since 1952. By 2014, all the fingernails on his left hand cumulatively measured 30 feet (9.1 meters) in length. His thumbnail alone was more than 6.5 feet (2 meters) in length.

Thanks to Chillal, we know that human fingernails can grow to at least 6.5 feet long, and perhaps more — hey, records are meant to be broken! His achievement, however, has come at a cost. Chillal has nerve damage in his left arm that has led to deafness in his left ear. His left hand is disfigured and his wrist is in constant pain. His family, who don't agree with his lifestyle, steers clear of helping him with daily tasks like buttoning his shirts. But Chillal can say he's a world record holder, earning the title of "longest fingernails on a single hand, ever."

Plus, he still has the title for "longest fingernails on a pair of male hands, ever" to beat. Melvin Boothe had fingernails on both hands that measured a combined length of 32 feet, 3.8 inches (9.85 meters) before his death in December 2009.