Adulthood is the stage of life when a person has grown up physically and is expected to take on the full responsibilities of managing their own life. In many countries, adulthood officially begins around age 18, when young people gain the legal right to vote, sign contracts, and make many of their own decisions without their parents' permission.

Becoming an adult involves much more than reaching a certain birthday. Adulthood means developing the ability to support yourself financially, make thoughtful decisions about important matters, and take responsibility for the consequences of your choices. An adult pays their own bills, shows up to work reliably, keeps their promises, and helps others when needed.

Different cultures mark the transition to adulthood in various ways. Some hold special ceremonies, while others simply recognize it when young people move out, start careers, or begin their own families. The journey into adulthood happens gradually: a 13-year-old babysitting younger siblings is practicing adult responsibility, while a 16-year-old with a first job is learning adult skills.

Scientists have discovered that the human brain continues developing into the mid-twenties, which helps explain why early adulthood often involves learning from mistakes and growing in wisdom. Reaching adulthood means gaining both freedom and responsibility: the freedom to make your own choices comes with the responsibility to live with the results, contribute to your community, and care for the people who depend on you.