Fingernails grow faster than toenails

Yes, but “four times” overstates the average difference in a measured sample. A study of healthy young adults found average fingernail growth of 3.47 mm per month and toenail growth of 1.62 mm per month—about 2.1 times faster. Other reviews cite typical estimates near 3 mm per month for fingernails and 1 mm for toenails. Growth varies by digit, age, and other factors, so the ratio is not fixed.