Enter your birth date to see the moon exactly as it looked on the night you were born: its phase, how much was lit and how old the lunar cycle was. Then find out which of your future birthdays land on a full moon.
Last updated:
The moon on the night you were born
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Illumination–
Moon age–
Nearest full moon–
Nearest new moon–
🌕 Birthdays on a full moon
Your next 12 birthdays
Birthday
Moon phase
Lit
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How to use the Birthday Moon Phase
Enter your birth date. Add the time of birth if you know it; otherwise the moon is shown for 9 pm that evening.
Choose your hemisphere so the drawing matches how the moon looks where you live.
Press Show my birth moon to see the phase, illumination and moon age.
Scroll down to see the full moon birthdays ahead and the phases of your next 12 birthdays.
Press Copy summary to share your birth moon.
The eight moon phases at a glance
Phase
Moon age (approx.)
Illumination
When it is visible
🌑 New Moon
0 days
0%
Not visible; up with the Sun during the day
🌒 Waxing Crescent
1–6 days
1–49%, growing
Western sky after sunset
🌓 First Quarter
about 7.4 days
50%
Afternoon and evening, sets near midnight
🌔 Waxing Gibbous
8–14 days
51–99%, growing
Most of the evening and night
🌕 Full Moon
about 14.8 days
100%
All night, rising at sunset
🌖 Waning Gibbous
16–21 days
99–51%, shrinking
Rises in the evening, visible into the morning
🌗 Last Quarter
about 22.1 days
50%
Rises near midnight, visible in the morning
🌘 Waning Crescent
23–29 days
49–1%, shrinking
Eastern sky before sunrise
How your birth moon is calculated
The Moon goes around Earth relative to the Sun once every synodic month of about 29.53 days. This tool finds the exact times of the new, first quarter, full and last quarter moons around your birth date with the series published by astronomer Jean Meeus, which is accurate to within a few minutes for dates from 1900 to 2100. The illuminated fraction comes from the Moon's phase angle i using k = (1 + cos i) ÷ 2, and the moon age is the time since the previous new moon.
A day is labeled New, First Quarter, Full or Last Quarter only when that exact moment falls on the calendar date in your time zone. Every other day gets one of the four in-between names. That is why a moon that looks full to the eye on the day before or after can still be labeled waxing or waning gibbous.
Why full moon birthdays come in patterns
235 synodic months (6,939.69 days) are almost exactly 19 calendar years (6,939.60 days). This near match, called the Metonic cycle, means the Moon's phase on any date repeats closely every 19 years. If you were born under a full moon, your 19th, 38th and 57th birthdays are good candidates for another one, give or take a day. The small mismatch slowly drifts the timing, so the pattern is not perfect over a lifetime.
Frequently asked questions
How do I find the moon phase on the day I was born?
Enter your date of birth and the tool computes the Moon's position relative to the Sun for that date using standard astronomical formulas (Jean Meeus' lunar phase algorithm). It shows the phase name, the percentage of the disc that was lit and the moon's age, the number of days since the previous new moon.
What are the eight moon phases?
New Moon, Waxing Crescent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Last (Third) Quarter and Waning Crescent. New, first quarter, full and last quarter are exact instants; the other four names describe the days in between.
How often does my birthday fall on a full moon?
Not often. A full moon lands on a given calendar date roughly once every 29.5 days, so in a typical year the chance is about 1 in 30. Because of the 19-year Metonic cycle, the moon's phase on your birthday nearly repeats every 19 years, so full moon birthdays tend to come in a pattern.
Why does the time of birth matter?
The illuminated fraction changes by up to about 12 percentage points per day around the quarter moons, and a principal phase such as the full moon happens at one exact moment. Adding your birth time gives the precise illumination when you were born. Without it, the tool uses 9 pm local time on that date.
Does my time zone change the result?
It can when a principal phase happens near midnight. The tool uses your device's time zone. If you were born far from where you are now and the phase changed close to midnight, the phase name may differ by one day from a calendar printed in your birthplace.
Why does the moon look reversed in the Southern Hemisphere?
Observers south of the equator see the Moon upside down compared with northern observers, so a waxing moon is lit on the left instead of the right. The hemisphere setting flips the drawing to match what you would see in the sky.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.