Example 1
- Date: 1990-05-15
Aquarius (Air)
L ≈ 303.8° → floor(303.8/30)=10 → Aquarius.
Moon sign (approximate) calculator
From the date you approximate the sign from the Moon mean ecliptic longitude. That is a sketch without an ephemeris, not a full sky position.
Here the moon sign is an approximation from mean longitude. This tool is for entertainment and learning, not fortune-telling or life advice. It does not replace personal, medical or financial decisions. Also try the moon phase and zodiac sign.
Result
Pick a date to see the approximate Moon sign.
How it works
The Moon sign in tropical astrology is the zodiac sign the Moon occupies at a moment. A full answer needs an ephemeris. This calculator shows only an educational approximation from mean longitude.
The method is explicit. We count days d from epoch J2000.0 (UTC noon on 1 January 2000), then mean longitude: L ≈ 218.3164477 + 13.17639648 × d (degrees). Sign = floor( (L mod 360) / 30 ) in order Aries → .. → Pisces.
This is mean longitude, not a true position with equation of center, nodes or parallax. Near sign boundaries the result can differ from a professional ephemeris by a full sign.
Example: 15 May 1990 → L ≈ 303.8° → sign Aquarius (air). 1 January 2000 → L ≈ 218.3° → Scorpio. 8 August 1988 → L ≈ 85° → Gemini.
Another case: 7 July 1977 → L ≈ 0.6° → Aries. 13 April 2013 → Taurus. 16 June 1994 → Virgo. The element shown is the sign’s element, as in the zodiac element tool.
Do not confuse this with moon phase (illumination vs the Sun) or the Sun sign (day and month in the tropics). They are separate calendar layers.
The model uses UTC noon on the chosen date, with no local clock time and no geographic longitude. Fine for classroom drills; not for a birth chart.
Astrology schools use ephemerides of different precision. Here the goal is one repeatable formula you can check without planetary libraries.
Treat the result as a drill on ecliptic longitude and the 12×30° split. Do not read it as fortune-telling, a personality diagnosis or life instruction.
Formula
d = JD(UTC noon of date) - 2451545.0
L = 218.3164477 + 13.17639648 × d (degrees; then L mod 360)
index = floor(L / 30) mod 12 → Aries...Pisces
Educational approximation. Not a lunar ephemeris.
How to use the calculator
- Type the value in “Date” using the unit printed on that label, not a different scale.
- Click Calculate or wait for the live result.
- Leave a blank field blank: the calculator errors out and does not fake a zero.
- The metric/US switch relabels units and does not convert a number you already typed.
- Compare with moon phase and Sun sign for that date.
Suggested uses
- Learn the ecliptic split into twelve 30° signs.
- Compare several dates and the Moon’s ~13°/day mean motion.
- Workshop: mean longitude vs a full ephemeris (error talk).
- Practice floor((L mod 360)/30) on concrete numbers.
- Pair with Sun sign and moon phase.
- Get a repeatable result without planetary software.
Examples
Example 2
- Date: 2000-01-01
Scorpio (Water)
L ≈ 218.3° → Scorpio (near the J2000 epoch).
Example 3
- Date: 1988-08-08
Gemini (Air)
L ≈ 85° → Gemini.
Example 4
- Date: 1977-07-07
Aries (Fire)
L ≈ 0.6° → Aries.
Example 5
- Date: 2013-04-13
Taurus (Earth)
L ≈ 57° → Taurus.
Example 6
- Date: 1994-06-16
Virgo (Earth)
L ≈ 176.1° → Virgo.
Example 7
- Date: 12
Result on the card after fill
What is moon sign (approximate) calculator of 12?
Example 8
- Date: 24
Result on the card after fill
What is moon sign (approximate) calculator of 24?
Related calculators
Frequently asked questions
What is the Moon sign in this calculator?
An educational approximation of the tropical sign from mean ecliptic longitude, not a full-ephemeris position.
Which formula do you use?
L ≈ 218.3164477 + 13.17639648×d, where d is days from J2000.0 (UTC noon). Sign = floor((L mod 360)/30).
Why is it only approximate?
Because we skip the equation of center, nodes, nutation and other corrections. Near boundaries it can disagree with the sky by a full sign.
Does clock time matter?
Not in this version. The model uses UTC noon on the chosen date. A birth-chart Moon sign needs an exact time.
How is Moon sign (approximate) calculator different from Moon phase?
Our zodiac sign is the tropical Sun from day and month. Here we approximate the Moon from the date.
Which date format should I use?
Prefer YYYY-MM-DD, e.g. 1990-05-15.
Is this fortune-telling or a birth chart?
No. The calculator is for entertainment and learning. It does not replace an ephemeris or life decisions.
What else should I check?
Moon phase, Sun sign, planetary day and approximate rising sign. Together they teach date layers without mixing precision.
What approximate Moon sign is 1990-05-15 versus 2000-01-01?
15 May 1990: Aquarius (Air). 1 January 2000: Scorpio (Water). Noon UTC, not a chart from birth time.
Does a blank date take today Moon sign?
No. Type 1990-05-15. A blank field is not Aquarius.