How is the zodiac sign determined?

The Western (tropical) zodiac assigns each birth date to one of twelve signs based on the sun's ecliptic longitude. The calculator simply looks up the month and day in the standard date ranges used by mainstream Western astrology.

What if my birthday is on a cusp date?

Cusp dates are settled by the standard tropical-zodiac ranges. For example, March 20 is the last day of Pisces and March 21 is the first day of Aries. The calculator returns whichever sign owns your exact day.

Are the date ranges the same every year?

The dates the Sun enters each sign actually drift by up to a day from year to year because of the leap-year cycle. The standard ranges used here are the rounded dates published by mainstream astrology references and accurate within about a day for any year.

What do element and modality mean?

Each sign belongs to one of four classical elements (Fire, Earth, Air, Water) and one of three modalities (Cardinal, Fixed, Mutable). Together they describe a temperament: Cardinal Fire (Aries) initiates with energy, Fixed Earth (Taurus) endures with steadiness, and so on.

What is a ruling planet?

Each zodiac sign is traditionally associated with a planet (the Sun and Moon are counted as planets in this scheme) thought to govern its character. Some signs have a classical ruler and a modern co-ruler — the calculator shows the classical ruler.

DATDate & Time

Zodiac Sign Calculator

Find your Western zodiac sign from your birth date. Returns the sun sign, its date range, element (Fire/Earth/Air/Water), modality (Cardinal/Fixed/Mutable), and ruling planet.

Date of birth

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How It Works

Formula

\text{sign}(m, d) = \text{lookup}(m, d \in \text{range}_i)

Where

$m$: Month of birth (1–12)
$d$: Day of birth (1–31)
$\text{element}$: Classical element of the sign (Fire, Earth, Air, or Water)
$\text{modality}$: Modality of the sign (Cardinal, Fixed, or Mutable)
$\text{ruler}$: Traditional ruling planet of the sign

Enter your date of birth. The calculator looks up the month and day in the twelve standard tropical-zodiac date ranges and returns the sign that contains your birthday, along with its element, modality, ruling planet, and unicode symbol.

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