The Qur'an was revealed over a period of how many years?

The Qur'an was revealed over a period of 23 years, from 610 CE to 632 CE. The revelation began when Prophet Muhammad (peace be upon him) was 40 years old, in the Cave of Hira on Mount Nur near Makkah, and continued until shortly before his death at the age of 63.

This 23-year period is traditionally divided into two phases. The Makkan period (approximately 13 years, 610-622 CE) focused primarily on matters of faith (aqidah), the oneness of Allah (Tawhid), stories of previous prophets, and moral teachings. The Madinan period (approximately 10 years, 622-632 CE) addressed social legislation, family law, economic regulations, and matters of governance for the growing Muslim community.

The gradual revelation served important purposes: it allowed Muslims to absorb and implement the teachings progressively, provided timely responses to events and questions as they arose, and made memorisation easier. This gradual method of revelation is known as tanzil (sending down in stages), as distinguished from a one-time delivery.