At what age does a person become an adult in Islam?

From Hidaya Foundation : > The person should be Muslim, **adult**, sane, free (not a slave). > They must posses a certain minimum amount of extra wealth (called nisab), fully owned by them in excess of personal use (such as clothing, food, shelter, household furniture, utensils, cars, etc). > They should have had this minimum amount in possession for a complete lunar year (hawl). The wealth should be of a productive nature, from which they can derive profit or benefit such as merchandise for business, gold, silver, livestock, etc. > The minimum amount (or Nisab) should not be owed to someone, i.e., it should be free from debt. The above states that a Muslim has **to be an adult** to give zakat. **Question:** At what age does a person become an adult in Islam? What **specific age in Sharia law** does a person **become an adult** so they are **obligated to give zakat**? *(Please include evidence from Qu'ran or Ahadith)*