The 8 Moon Phases Explained (and What Each One Looks Like)

The moon looks different every night, and over about a month it moves through eight recognizable shapes. Once you know the pattern, you can glance up and know roughly where you are in the cycle. Here is each phase in plain language.

Why the moon changes shape

The moon does not make its own light. It reflects the sun. As the moon orbits Earth, we see different amounts of its sunlit side. When the lit side faces away from us we see almost nothing (a new moon). When it faces us fully we see a bright full moon. Everything in between is just how much of that lit half is pointed our way.

The whole cycle, from one new moon to the next, takes about 29.5 days.

The 8 phases, in order

• New Moon. The moon sits between Earth and the sun, so the side facing us is dark. You basically cannot see it. This is the start of the cycle.
• Brightening Crescent. A thin sliver of light appears on one side and starts to grow. "Brightening" just means it is getting more lit each night.
• Half Full. Half of the disc is lit and it is still growing. (Astronomers call this "first quarter," which confuses people because it looks like a half, not a quarter.)
• Almost Full. More than half is lit now, filling in toward a full moon.
• Full Moon. The whole face is lit. This is the brightest night and the one most people notice.
• Just Past Full. The light starts to shrink back from one edge.
• Half Empty. Down to half lit again, now shrinking. (Astronomers call this "last quarter.")
• Fading Crescent. A thin sliver, getting smaller each night, until it disappears back into a new moon and the cycle starts over.

Waxing vs waning (the easy way to remember)

You will hear the words "waxing" and "waning." They just mean:

• Waxing = getting brighter, growing toward full.
• Waning = getting dimmer, shrinking toward new.

That is the only jargon you really need. Growing or shrinking.

How to tell which phase you are looking at

If the moon is a crescent and the light is on the right (in the Northern Hemisphere), it is usually growing. If the light is on the left, it is usually shrinking. And if you would rather not squint at the sky and guess, you can just check tonight's exact phase and how lit it is on moontrack.

Want to go deeper on the app itself? Read how to use moontrack.