New Moon: When the moon is not visible because it is located between the Earth and the Sun. Illumination: 0%. Waxing Crescent: When a small sliver of the moon becomes visible, growing larger each night after the new moon. Illumination: 1%–49%. First Quarter: When half of the moon's face is illuminated, occurring approximately one week after the new moon. Illumination: ~50%. Waxing Gibbous: When more than half of the moon is illuminated, leading up to a full moon. Illumination: 51%–99%. Full Moon: When the entire face of the moon is illuminated by the Sun, appearing as a complete circle. Illumination: 100%. Waning Gibbous: When the moon begins to shrink after a full moon, but more than half of it remains illuminated. Illumination: 99%–51%. Last Quarter: When half of the moon's face is illuminated again, occurring approximately one week after the full moon. Illumination: ~50%. Waning Crescent: When only a small sliver of the moon remains visible before the new moon. Illumination: 49%–1%. Illumination: The percentage of the moon’s surface that is lit by the Sun, which varies depending on the phase of the moon.