The length of a moon cycle, also known as a synodic month, is about 29.5 days. This is the time it takes for the Moon to complete one full cycle of phases, from new moon to new moon

. This cycle is longer than the Moon's actual orbit around Earth, which takes about 27.3 days (called a sidereal month). The difference occurs because as the Moon orbits Earth, the Earth is also moving around the Sun, so the Moon must travel a bit further to reach the same phase position relative to the Sun and Earth

. In summary:

• Synodic month (moon phase cycle): ~29.5 days
• Sidereal month (orbit relative to stars): ~27.3 days

The lunar cycle includes eight phases: new moon, waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, third quarter, and waning crescent, all completed in about 29.5 days