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Zodiac Sign Calculator on ToolsVortex with a worked example filled in

Zodiac Sign Calculator

ToolsVortex · Date & Time

Enter your birth date to see your Western sun sign, its element and modality, the opposite sign, and a note if you were born on a cusp day between two signs.

Your sun sign
♌ Leo
July 23 to August 22
FireElement
FixedModality
AquariusOpposite sign

Runs in your browser. Nothing you type is sent anywhere. For entertainment only.

Zodiac Sign Calculator on ToolsVortex with a worked example filled in
Zodiac Sign Calculator: a July 25, 1990 birthday shown as Leo, a fixed fire sign opposite Aquarius.

This zodiac sign calculator is for anyone curious about the star sign linked to their birthday, whether for a horoscope, a gift or a party game. You get the sun sign, its element and modality, the opposite sign, and a warning when your birthday sits on the border between two signs. Astrology is a belief system, not a science, so treat the result as entertainment.

How Do You Find Your Zodiac Sign From Your Birth Date?

Your zodiac sign is the sign the Sun was in on your birthday, so you match your month and day to the 12 date ranges. For example, July 25 falls between July 23 and August 22, so the sign is Leo, a fixed fire sign. Birthdays on the edge of a range are cusp dates.

What Are the Zodiac Sign Dates?

The 12 Western zodiac signs each cover about 30 days, starting with Aries at the March equinox.

SignDatesElementModality
♈ AriesMarch 21 to April 19FireCardinal
♉ TaurusApril 20 to May 20EarthFixed
♊ GeminiMay 21 to June 20AirMutable
♋ CancerJune 21 to July 22WaterCardinal
♌ LeoJuly 23 to August 22FireFixed
♍ VirgoAugust 23 to September 22EarthMutable
♎ LibraSeptember 23 to October 22AirCardinal
♏ ScorpioOctober 23 to November 21WaterFixed
♐ SagittariusNovember 22 to December 21FireMutable
♑ CapricornDecember 22 to January 19EarthCardinal
♒ AquariusJanuary 20 to February 18AirFixed
♓ PiscesFebruary 19 to March 20WaterMutable

The Sun crosses from one sign to the next at a slightly different time each year, so the first and last day of each range can shift by a day. That is why the tool flags those cusp dates.

How Is a Sun Sign Worked Out?

A sun sign is the 30 degree slice of the sky the Sun appeared to sit in on the day you were born. The Sun’s yearly path across the sky is called the ecliptic. Western astrology uses the tropical zodiac, which splits the ecliptic into 12 equal signs of 30 degrees each, starting from the vernal equinox, the March point where the Sun crosses the celestial equator. The tool simply compares your month and day with the start date of each sign.

sign = the last sign whose start date is on or before your birthday
360 degrees ÷ 12 signs = 30 degrees per sign

What Do the Elements and Modalities Mean?

Each sign belongs to one of four elements and one of three modalities, so no two signs share both. The element groups are fire (Aries, Leo, Sagittarius), earth (Taurus, Virgo, Capricorn), air (Gemini, Libra, Aquarius) and water (Cancer, Scorpio, Pisces). The modality describes where a sign sits in its season: cardinal signs start a season, fixed signs sit in the middle and mutable signs close it. The opposite sign is the one 180 degrees away, six signs along.

Why Does My Zodiac Sign Not Match the Stars?

Your sign and the constellation behind the Sun no longer match because of precession, a slow wobble of Earth’s axis that shifts the equinox about one degree every 72 years. Over roughly 2,000 years this has moved the signs nearly a full sign away from the constellations they are named after. The Sun also passes through Ophiuchus, a 13th constellation, from late November to mid December, but the tropical zodiac does not include it. NASA notes that astrology claims are not based on scientific evidence, unlike astronomy. To find the weekday you were born on, try the day of the week calculator, and for your exact age in years, months and days, use the age calculator.

Worked Example

Sam was born on July 25, 1990. Enter that date and the tool shows ♌ Leo, because July 25 falls between July 23 and August 22. The boxes show the element Fire, the modality Fixed and the opposite sign Aquarius. Change the date to March 20, 1990 and the result is Pisces with a cusp warning, since March 20 is the last day of Pisces and the Sun moves into Aries around March 20 or 21. To count the days until your next birthday, use the days between dates calculator.

How Do You Use the Zodiac Sign Calculator?

  1. Enter your birth date

    Pick or type your birth date. The year does not change the sign.

  2. Read your sun sign

    The big text shows the sign symbol and name.

  3. Check the date range

    The line below shows the full date range for that sign.

  4. See element and modality

    The boxes show the element, modality and opposite sign, plus any cusp note.

How to use the Zodiac Sign Calculator, steps 1 to 4 numbered on the tool
The numbers on the picture match the steps above.

Frequently Asked Questions

What zodiac sign is February 29?

February 29 is Pisces. Pisces runs from February 19 to March 20, so a leap day birthday sits well inside that range and never falls on a cusp.

What is a cusp birthday?

A cusp birthday is the first or last day of a sign's date range. The Sun changes sign at a different time each year, so someone born on March 20 or 21 may be Pisces or Aries depending on the year and birth time.

Does the birth year change my zodiac sign?

Only on cusp days. For most birthdays the month and day alone decide the sign. On the edge days, the exact moment the Sun changed sign that year, which can shift by about a day, decides it.

How many zodiac signs are there?

The Western tropical zodiac has 12 signs, each covering 30 degrees of the ecliptic. Some people mention Ophiuchus as a 13th sign, but it is a constellation and is not part of the tropical zodiac used in horoscopes.

Is the zodiac sign the same as the Chinese zodiac?

No. The Western zodiac uses 12 signs based on the Sun's place in the sky by month. The Chinese zodiac uses 12 animals in a cycle of years that start at Lunar New Year.

Is astrology scientifically proven?

No. Controlled tests have not shown that sun signs predict personality or events, and NASA describes astrology claims as not based on scientific evidence. Use your sign for fun, not for decisions.

Sources and Further Reading

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Last reviewed: October 2026