The fingernail develops about a tenth of a millimetre every day and approximately 3.47 millimetres every month. If you lose the nail due to any reason, it may take up to 6 months for it to regrow fully. They grow quickly in the day, and the summer because the fingernails grow faster than toenails. The toenails grow about 1.62 millimetres per month, and if you lose your toenail, it will take one and a half years for it to grow back completely. There are lots of factors that affect the nail’s growth, such as your age, overall health, and hormones.