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Sun sign calculator

The dates printed in magazines are rounded. This one computes where the Sun actually was on the day you were born.

The date is enough on most days. If you were born within a day of a sign boundary, add your time and city, because then the answer really does depend on the hour.

The city sets the time zone, so the result stops depending on guesswork.

Almost every site will tell you that Taurus runs from 21 April to 21 May. That is a rounded average, not a fact. The Sun enters a sign at a precise moment that shifts by roughly a day across the four-year leap cycle, so in some years Taurus begins on 19 April and in others on 20 or 21 April. If your birthday sits near one of those edges, the table you looked at as a child may simply have been wrong for your year.

This calculator does not look anything up. It computes the Sun position for your birth date with the Swiss Ephemeris and then finds the exact moment the Sun entered your sign, and the moment it leaves, in your birth year specifically. If your birth falls inside the uncertainty window, it says so instead of picking a side.

How to read the result

Your sign, and the window it belongs to

You get the sign, the degree the Sun occupied within it, and the two real boundary moments of that sign in your birth year, in UTC.

Being on the cusp is a real state, not a personality type

Astrologically a placement is in one sign or the other, never in both. What is real is that without an exact birth time we may not be able to tell which, and in that case we show both.

The Sun is the slow, safe one

The Sun moves about one degree a day, so unlike the Moon or the Ascendant your sign is stable across the whole day for all but the boundary cases.

Zodiac sign questions

What is a sun sign?

It is the zodiac sign the Sun occupied at the moment you were born, and it is what people mean by "my sign" in everyday conversation. It describes the core of the chart, though it is only one of many placements.

Why do different sites give me different dates?

Because most of them print one fixed table for every year. The Sun does not cooperate: its entry into each sign drifts by about a day over the leap-year cycle. A site that says Taurus always starts on 21 April is wrong roughly one year in four.

I was born on the cusp. Which sign am I?

One of them, and this calculator will tell you which if you give your birth time and city. Without them, if your birth falls inside the uncertainty window, we show both possibilities and the exact moment of the change rather than guessing.

Does birth time matter for the sun sign?

Usually not. The Sun spends about a month in a sign, so a few hours change nothing except within a day of a boundary. Birth time matters enormously for the Ascendant and quite often for the Moon.

Why does Indian astrology give me another sign?

Because it measures the zodiac from the stars rather than from the spring equinox, and the two frames have drifted about 24 degrees apart. That is a different question with its own calculator on this site.

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