Multiple choice general knowledge An average human Nails grow ---------- inches in every 24 hours 0.00006 0.00007 0.00008 0.00009 Reveal answer Fill a bubble to check yourself B Correct answer Explanation Fingernails grow at approximately 3.47 mm per month, or about 0.115 mm per day. Converting this to inches (0.115 mm ÷ 25.4) gives approximately 0.00007 inches per day. Toenails grow more slowly, but this question refers to average nail growth.