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Zodiac Sign Calculator

Find your zodiac sign (sun sign) from your birth date, with its element, modality, ruling planet and the Sun’s exact position, including a check for cusp birthdays.

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Uses the Sun’s real position on your birth date at 12:00 UTC from the US Naval Observatory formula, so cusp dates are handled correctly. If you were born within about a day of a sign change, your exact birth time and place decide your sign. Astrology is for fun; it has no scientific support.

Quick Answer

Your zodiac sign is the 30° slice of the sky the Sun was in on your birthday. On June 15, 1990 the Sun was at 24.1° Gemini, so the sign is Gemini, an air sign with mutable modality. Usual dates are Aries March 21 to April 19, Taurus April 20 to May 20 and so on, but the change days shift by a day from year to year.

Last updated: 10 November 2026 ·How we calculate this: the US Naval Observatory’s approximate solar position formula

How This Zodiac Sign Calculator Works

Western astrology splits the Sun’s yearly path across the sky (the ecliptic) into twelve equal 30° signs, starting with Aries at the March equinox. Your sun sign, the one people mean by “your sign”, is where the Sun was on the day you were born. Most charts print fixed date ranges, but the Sun reaches each sign at a slightly different time each year. This calculator works out the Sun’s actual position on your birth date, so it gets cusp birthdays right.

Quick explanation: your birthday picks the sign, and the sign gives the element and modality.

  • Elements: Fire, Earth, Air and Water, repeating every four signs.
  • Modalities: Cardinal, Fixed and Mutable, repeating every three signs.
  • Cusp: within about a day of a change, the birth time decides.

How to Use the Zodiac Sign Calculator

  1. Enter your birth date as year-month-day.
  2. Press Calculate.
  3. Read your sign, element, modality and ruling planet.
  4. Check the cusp note if your birthday is near a sign change.
  5. Use your exact birth time if the note says the time decides.

How the Sun’s Position Is Found

  • Days from J2000: D = Julian date − 2451545.0 (noon on January 1, 2000)
  • Mean anomaly: g = 357.529 + 0.98560028 × D degrees
  • Mean longitude: q = 280.459 + 0.98564736 × D degrees
  • Ecliptic longitude: L = q + 1.915 sin g + 0.020 sin 2g
  • Sign: floor(L ÷ 30), counting 0 = Aries, 1 = Taurus, up to 11 = Pisces

The US Naval Observatory gives this formula as accurate to about 1 arcminute between 1800 and 2200, which is about 25 minutes of time, plenty for sun signs.

Key Terms

  • Sun sign: the zodiac sign the Sun was in at birth.
  • Ecliptic: the Sun’s yearly path across the sky, measured in degrees of longitude.
  • Cusp: the boundary between two signs.
  • Tropical zodiac: signs measured from the March equinox, used in Western astrology.
  • Modality: Cardinal, Fixed or Mutable, the quality of a sign.

Worked Example

Someone was born on March 20, 2000, the day of the spring equinox.

  • At noon UTC that day the Sun was at 0.19° of ecliptic longitude
  • That is 0.19° into Aries, so the sign is Aries
  • The Sun crossed 0° about 07:37 UTC that morning, so someone born before then in UTC is a Pisces
  • Printed charts that start Aries on March 21 would have given the wrong sign

Real-Life Examples

  • Cusp birthdays: see whether March 20 or 21, or December 21 or 22, is the earlier or later sign in your birth year.
  • Friends and family: November 3, 1985 is a Scorpio (Water, Fixed).
  • Gifts and cards: find a sign for birthstone or horoscope themed presents.
  • Learning: see how the Sun moves about 1° a day along the ecliptic.

Sun Sign vs Moon Sign vs Rising Sign

  • Sun sign: where the Sun was on your birthday. Needs only the date.
  • Moon sign: where the Moon was. It changes every two to three days, so it needs the date and often the time.
  • Rising sign: the sign on the eastern horizon. It changes about every two hours, so it needs the exact time and place.

Zodiac Signs, Elements and 2026 Start Dates

Start dates from the same solar formula; in other years they can move by a day.

SignElementModalityStarts in 2026 (UTC)
♈ AriesFireCardinalMar 20
♉ TaurusEarthFixedApr 20
♊ GeminiAirMutableMay 21
♋ CancerWaterCardinalJun 21
♌ LeoFireFixedJul 22
♍ VirgoEarthMutableAug 23
♎ LibraAirCardinalSep 23
♏ ScorpioWaterFixedOct 23
♐ SagittariusFireMutableNov 22
♑ CapricornEarthCardinalDec 21
♒ AquariusAirFixedJan 20
♓ PiscesWaterMutableFeb 18

Signs, Elements and Modalities

The four elements group the signs by temperament in astrology: Fire (Aries, Leo, Sagittarius), Earth (Taurus, Virgo, Capricorn), Air (Gemini, Libra, Aquarius) and Water (Cancer, Scorpio, Pisces). The three modalities describe how a sign acts: Cardinal signs start each season, Fixed signs sit in the middle and Mutable signs end it.

Astrological signs are not the same as the constellations. The tropical zodiac is tied to the seasons, while the constellations have slowly shifted because Earth’s axis wobbles (precession). That is why the Sun is actually in front of the constellation Pisces at the March equinox today, and why stories about a “13th sign”, Ophiuchus, appear now and then. They describe astronomy, not the tropical signs astrology uses.

Your full birth chart also has a moon sign and a rising sign, which need the exact birth time and place. This calculator gives the sun sign only.

Common Mistakes to Avoid

  • Trusting fixed date charts on cusp days. The change day moves between years.
  • Ignoring time zones. A late-evening birth in the Americas is already the next day in UTC.
  • Confusing signs with constellations. Astrology’s signs follow the seasons, not the stars.
  • Expecting a moon or rising sign. Those need the birth time and place.
  • Entering the date the wrong way round. Use year-month-day.

Frequently Asked Questions

Enter your birth date above. Your sun sign is the 30° slice of the ecliptic the Sun was in on that day.

Roughly Aries March 21 to April 19, Taurus April 20 to May 20, Gemini May 21 to June 20, Cancer June 21 to July 22, Leo July 23 to August 22, Virgo August 23 to September 22, Libra September 23 to October 22, Scorpio October 23 to November 21, Sagittarius November 22 to December 21, Capricorn December 22 to January 19, Aquarius January 20 to February 18 and Pisces February 19 to March 20.

The calculator gives the hour the Sun changed sign; compare it with your birth time converted to UTC.

Fire, Earth, Air and Water. Each covers three signs.

Ophiuchus is a constellation the Sun passes, but it is not part of the twelve tropical signs.

No. Signs are equal 30° slices from the March equinox; constellations are uneven star patterns.

There is no scientific evidence that signs predict personality or events; treat it as entertainment.

A calendar year is not exactly as long as the Sun’s yearly cycle, and leap years shift dates, so the change moves by up to a day.

That is a different system based on the lunar year; use the Chinese Zodiac Calculator.

References & Sources

SourceUsed ForLink
US Naval Observatory, Approximate Solar Coordinates Formula for the Sun’s ecliptic longitude, accurate to about 1 arcminute from 1800 to 2200. https://aa.usno.navy.mil/faq/sun_approx
US Naval Observatory, Earth’s Seasons and Apsides Equinox and solstice times, the start points of Aries, Cancer, Libra and Capricorn. https://aa.usno.navy.mil/data/Earth_Seasons