Skip to content

Free calculator · Astrology

Mercury Sign Calculator

Your Mercury sign is the sign of the zodiac Mercury stood in when you were born. Mercury never moves more than 28 degrees from the Sun, so your Mercury sign is your Sun sign or one of its two neighbours. The calculator works it out the way the UmbraLux app does, to the arcminute.

Date of birth

As exact as you can, ideally from your birth certificate.

Your place is missing? Take the nearest town; a few kilometres hardly change the result.

The calculation runs in your browser. Your birth data is neither sent nor stored; only this device remembers your last entry. · Place data: GeoNames (CC BY 4.0)

How the Mercury sign is calculated

The calculator runs the same calculation as the UmbraLux app, in three steps:

  1. 1

    Turn the clock time into Universal Time

    Your birth time is the clock time at your birthplace. With the time zone that applied there on that day (the IANA time zone database knows summer times and older rules), it becomes Universal Time (UTC). Without a time, the calculator takes your whole birthday at your birthplace.

  2. 2

    Calculate the position of Mercury

    For that moment the ephemeris gives the apparent geocentric longitude of Mercury on the ecliptic of date: where Mercury stood in the zodiac, seen from the Earth.

  3. 3

    Read the sign

    The longitude divided by 30° gives the sign: 0° to 30° is Aries, 30° to 60° Taurus and so on (tropical zodiac). The remainder is the degree within the sign.

Example: 15 May 1990, 14:30, Berlin

On 15 May 1990 summer time applied in Berlin (UTC+2), so 14:30 was 12:30 Universal Time. At that moment Mercury stood at 8°00′ Taurus, moving retrograde.

Mercury had entered Taurus on 4 April 1990 and left it on 12 June 1990: anyone born in that time has Mercury in Taurus.

What the Mercury sign means in astrology

Astrology reads Mercury as your way of thinking, learning and speaking: how you take in information, order it and pass it on.

In the library

Questions about the Mercury sign

How long does Mercury stay in a sign?

Mostly just under three weeks (19 days at the median). When it crosses a border while retrograde, it stays only a few days or up to 70 days in the same sign (calculated for 1900 to 2100).

What does a retrograde Mercury at birth mean?

About three times a year Mercury seems to move backwards, seen from the Earth, for 19 to 25 days; it is retrograde at about one birth in five. Astrology reads it as inward, examining thought. The calculator shows whether Mercury was retrograde at your birth.

How accurate is the calculator?

In 5,000 samples from 1900 to 2100 Mercury lay two arcseconds on average and 15 at most from a calculation on the Swiss Ephemeris.

Is my data stored?

No. The calculation runs in your browser; your date, time and place are neither sent nor stored. Only your device remembers your last entry, and you can delete it below the form.

Sources

More calculators

All calculators