A date. A Moon. Your beginning.
The Moon on
your birthday.
Was it a bright full Moon or a slender crescent? Find the phase for the day you were born, then turn it into a card to keep or share.
Start with a date
Find your birthday Moon
No account. No email. Your birthday stays in this page unless you choose to export it or open the map designer.
A small part of your story.
Enter your birthday to discover the Moon’s phase, then keep it as a free card.
What is a birthday Moon?
Your birthday Moon is the phase of the Moon at a chosen moment on your birth date. As the Moon orbits Earth, we see different amounts of its sunlit half. The sequence runs from new Moon through waxing crescent, first quarter and waxing gibbous to full Moon, then through the waning phases back to new Moon.
The percentage is the illuminated fraction of the disc facing Earth. It is not the percentage of the whole Moon receiving sunlight, and it does not describe how bright the Moon looked through clouds or daylight.
Why might the time change my result?
The Moon changes continuously. A date covers 24 hours, so we calculate at 12:00 UTC unless you provide more detail. With a selected birthplace, the tool uses its local time zone and defaults to local noon. A known birth time gives a more specific instant. Near a phase boundary, different times on the same date may have different phase names.
The phase is essentially the same worldwide at the same instant. Your location changes the local clock and the way the Moon appears oriented. Our illustration uses a simple northern or southern hemisphere convention; it does not simulate your viewing angle.
How we calculate it
We use Astronomy Engine to calculate the Moon–Sun phase angle and illuminated fraction for the selected instant. Phase names describe neighborhoods around new, quarter and full Moon; they are not exact event timestamps. The supported date range is 1900–2100.
The surface illustration uses the NASA CGI Moon Kit texture. Credit: NASA / Goddard Space Flight Center Scientific Visualization Studio / Arizona State University. It is a rendered illustration, not a photograph taken on your birthday. If the texture cannot load, the calculated phase still displays.
You can compare the result with an independent Moon phase calendar using the same UTC instant. Read more about our astronomy and its limits.
Keep the Moon. Explore the stars.
Download a square card for a post or a portrait card for a story. Both are free PNG files. Sharing a card reveals its chosen date and time, so share only what you are comfortable making public.
For the complete sky, create a personalized star map with constellations, planets and your own words. No account or purchase is needed.
Does my birth phase predict my personality?
This calculator describes astronomy. It does not assign personality traits, predict events, or score relationship compatibility. A birthday Moon can still be a meaningful keepsake without making those claims.