Question: how long does it take to grow an inch of nail?
Answer: Your fingernails grow at an average rate of 3.47 millimeters (mm) per month, or about a tenth of a millimeter per day. To put this in perspective, the average grain of short rice is about 5.5 mm long. If you happen to lose a fingernail, it may take up to six months for that nail to completely grow back.