Zodiac decan calculator

Zodiac decan calculator: what it is for

From your date of birth, the tool calculates the exact position of the Sun and shows which decan of the sign you were born in, the degree, the ruling planet in the triplicity system and the dates of each of the three decans of your sign that year, which change slightly from year to year.

Everything is calculated in your browser, with no sign-up and without sending your date of birth to a server. Astrology is a cultural tradition with no scientific evidence: use it for fun.

How to use

1. Enter your date of birth.
2. Add the time if you want more precision.
3. See the decan, the ruler and the dates.

When to use it

• Understanding differences between people of the same sign.
• Curiosity about astrology.
• Content for social media.

Frequently asked questions

What is a decan?

Each sign covers 30 degrees of the zodiac and is split into three parts of 10 degrees, the decans, of about 10 days each. In astrology, the decan gives the Sun sign a different tone, because each one has its own ruling planet.

Who rules each decan?

In the most common system, the triplicities, the 1st decan is ruled by the sign's own ruler, and the 2nd and 3rd by the rulers of the next signs of the same element. In Aries, for example, they are Mars, the Sun (from Leo) and Jupiter (from Sagittarius).

Why do the dates change a little from year to year?

Because the dates depend on when the Sun passes each degree of the zodiac, which varies by up to a day from one year to the next. That is why the tool calculates the Sun's position on your date of birth instead of using a fixed table. Astrology is for entertainment.

Is it really free?

Yes, 100% free. No sign-up, no subscription and no usage limits. All Tools123 tools are free and run right in your browser.

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