The lunar cycle on any date
Moon Phase Calculator
Use this free Moon Phase Calculator to see the lunar phase for today, your birthday or any date between 1900 and 2100. It shows the phase name, how much of the Moon is lit, the Moon’s age in days and the exact time of the next New Moon, Quarter and Full Moon in your own time zone, with the working displayed beneath.
Find the Moon phase for any date
The form opens with the current date and time so you see today’s Moon phase straight away. Change the date to check a birthday or any other day. The calculation runs in your browser; nothing you enter is sent to the site.
Your Moon phase result
A symbolic reading
Remember: the phase is astronomy, but its meanings come from tradition and are offered for curiosity and self-reflection, not as scientific findings or predictions.
Where this date sits in the cycle
Upcoming Moon phases
| Phase | Exact time | From now |
|---|
How this was calculated
How to use the Moon Phase Calculator
- Check the date. It starts as today, and you can change it to your birthday or any other day.
- Enter a time on a 24-hour clock, or leave it blank to use midday.
- Choose the time zone for the place and moment you are asking about. The first option is your device’s own time zone.
- Select Calculate moon phase. To return to the present moment, choose Use current date and time.
- Read the phase, illumination and Moon age, then scroll to see the next New, Quarter and Full Moons.
What is a Moon phase?
A lunar phase describes how much of the Moon’s sunlit half we can see from Earth. The Moon is always half lit by the Sun, but as it orbits Earth the angle between the Moon, Earth and Sun changes, so we see different amounts of the lit side. That is why the Moon seems to grow from a thin crescent to a full disc and back again over roughly 29.5 days, a period known as the synodic month.
People ask for the “moon phase today”, the “moon phase on my birthday” or “what moon phase was I born under” for many reasons, including astronomy, gardening, photography, journaling and astrology. This lunar phase calculator answers the astronomical question precisely and keeps the symbolic reading clearly separate.
Method and formula used
SOULTRIANGLE calculates the Moon’s and the Sun’s positions directly instead of looking them up in a table. The phase follows from the angle between them.
Step 1: Convert your local date and time to UTC using the time zone you chose, including daylight saving rules for that date.
Step 2: Convert UTC to a Julian Day number.
Step 3: Calculate the Moon’s ecliptic longitude with a 60-term series from Jean Meeus’s Astronomical Algorithms, and the Sun’s apparent longitude with standard orbital elements.
Step 4: Subtract to get the elongation, the Moon-Sun angle from 0° to 360°. Illumination = (1 − cos elongation) ÷ 2.
Step 5: Name the phase from the elongation in 45° bands, so New Moon covers 337.5° to 22.5° and Full Moon covers 157.5° to 202.5°.
Step 6: Find the exact times when the elongation reaches 0°, 90°, 180° and 270° by repeated refinement, and measure Moon age from the last New Moon.
The eight-phase naming convention is a common one, but sources differ on where a “Full Moon” begins and ends. We state our bands so you can compare. Exact New, Quarter and Full Moon times do not depend on that choice.
Worked example: August 24, 1990 at 14:30 in Karachi
Karachi used UTC+05:00 on that date, so 14:30 local time is 09:30 UTC. At that moment the Moon was at about 17° Libra and the Sun about 1° Virgo. The Moon was roughly 3.9 days past the New Moon, with the lit part at about 16 percent, which makes it a Waxing Crescent. The next First Quarter fell a few days later, on August 28.
Try the same inputs in the calculator to see the full working, or enter your own birth date to see which phase the Moon was in when you were born.
The eight Moon phases explained
Each phase has a physical description, plus a traditional symbolic association. The symbolic notes are cultural and astrological, not scientific.
| Phase | What you can see | Traditional association |
|---|---|---|
| New Moon | The Moon sits close to the Sun in the sky and its lit side faces away from us, so it is effectively invisible. | Often linked with quiet intentions and fresh starts. |
| Waxing Crescent | A thin sliver appears low in the west after sunset and grows each night. | Often linked with first steps and gathering energy. |
| First Quarter | Half the disc is lit, on the right in the Northern Hemisphere. It is high in the sky at sunset. | Often linked with decisions and effort. |
| Waxing Gibbous | More than half is lit and increasing, and the Moon is up for much of the evening. | Often linked with refining and adjusting plans. |
| Full Moon | The whole face is lit and the Moon rises around sunset and sets around sunrise. | Often linked with visibility, celebration and release. |
| Waning Gibbous | The lit part shrinks, and the Moon rises later each evening. | Often linked with sharing and gratitude. |
| Last Quarter | Half is lit again, now on the left in the Northern Hemisphere, and the Moon is high at sunrise. | Often linked with letting go and reviewing. |
| Waning Crescent | A thin crescent shows in the east before sunrise. | Often linked with rest and reflection. |
Moon phase on your birthday
To find the Moon phase on your birth date, enter the date, your birth time if you know it and the time zone that applied at your birthplace. A birth-time error of a few hours changes the illumination by only a few percent, so the phase name usually stays the same unless you were born close to a boundary. If the result sits near the edge of two phases, the tool’s exact-time table helps you see which side you were on.
Birthday Moon phases are popular in astrology and as keepsake facts, but they do not define a personality. For the zodiac position of the Moon at birth, use the Moon Sign Calculator.
Moon phase versus Moon sign
The phase tells you how lit the Moon appears, and it repeats every 29.5 days. The Moon sign tells you which zodiac sign the Moon is in, and it changes about every two and a half days. A New Moon in Leo and a Full Moon in Aquarius are two separate pieces of information. The result panel shows both, using the tropical zodiac.
Who may find this tool useful?
The calculator may help stargazers planning a dark-sky night, photographers looking for a full Moon rise, gardeners who follow lunar calendars, writers checking the Moon in a historical scene, and anyone curious about a birthday or anniversary. It can also support reflective habits such as setting intentions at a New Moon.
It should not be used for medical, financial or legal decisions. Lunar traditions can be meaningful, but they do not predict outcomes.
Common mistakes and limitations
- Using the wrong time zone: an exact Full Moon can fall on different calendar dates in different zones.
- Mixing 12-hour and 24-hour time: 2:30 in the afternoon is 14:30.
- Expecting the same view everywhere: in the Southern Hemisphere the lit side appears on the opposite side. The Hemisphere selector flips the picture.
- Treating the percentage as exact: illumination is an approximation from the Moon-Sun angle, and the visible fraction also depends slightly on the Moon’s distance and your location.
- Confusing phase with sign: they are different measurements.
- Reading a symbolic meaning as a forecast: traditions offer themes, not guarantees.
Frequently asked questions
How do I find the Moon phase on my birthday?
Enter your birth date in the calculator, add your birth time if you know it, and choose the time zone of your birthplace. The tool converts that moment to universal time, calculates where the Moon is relative to the Sun and names the phase. If you do not know your birth time, the default of 12:00 gives a good estimate, because the phase changes slowly over a day.
What are the eight Moon phases?
In order they are New Moon, Waxing Crescent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Last Quarter and Waning Crescent. Waxing means the lit part is growing, and waning means it is shrinking. The full cycle takes about 29.5 days.
What does Moon age mean?
Moon age is the number of days since the most recent New Moon. It runs from 0 to about 29.5. A Moon age near 7 is close to First Quarter, near 15 is close to Full Moon, and near 22 is close to Last Quarter.
How accurate is this lunar phase calculator?
The calculator computes the Moon and Sun positions with published astronomical series. When we checked the timing of ten well-known New, Quarter and Full Moons from 1999 to 2025, the results fell within about two minutes of published almanac times. Illumination is derived from the Moon-Sun angle and is an approximation of a few tenths of a percent.
Why does the Full Moon time differ from other websites?
A Full Moon is an exact instant, but many sites show only the date, and the date depends on the time zone. A Full Moon late in the evening in New York can fall on the next calendar day in Pakistan or Australia. This tool shows the exact time in the zone you choose.
Is the Moon phase the same as the Moon sign?
No. The phase describes how much of the Moon is lit as seen from Earth, which depends on the angle between the Moon and the Sun. The Moon sign is the zodiac sign the Moon is travelling through. The tool shows both, and you can explore the sign in more detail with the Moon Sign Calculator.
Does the Moon phase affect my personality or the future?
The Moon phase itself is an astronomical fact, but its symbolic meanings belong to astrology and cultural tradition. They are not scientifically established and cannot predict events or define a person. Treat the interpretations as prompts for reflection.
Is my date or time saved?
No. The calculation runs in your browser and the date, time and time zone you enter are not sent to the SOULTRIANGLE server by this tool. Ordinary hosting logs and other site-level technologies may operate separately, as described in the Privacy Policy.
Related tools and resources
Keep exploring cycles, the Moon and numerology, or read how SOULTRIANGLE documents its methods.
Our commitment to transparency
We explain the method, show the working and aim to correct problems when they are reported. If you spot an error, please use our Contact page and include the tool name and a non-sensitive example. You can also read How We Calculate and the Disclaimer.
Last updated: October 18, 2026 · Method: Moon and Sun longitudes (Meeus series), elongation-based phase and illumination; event times typically within a few minutes.