Mercury sign calculator

Mercury is the planet astrologers read for the mind at work: how you take in information, how you make decisions, how you talk, write and argue, and what kind of learning sticks. Your Mercury sign is the part of the zodiac Mercury stood in at the moment of your birth. It helps explain why two people with the same Sun sign can think in completely different ways, one in lists, one in pictures, one out loud.

From Earth, Mercury never appears more than about 28 degrees from the Sun. Your Mercury sign is therefore either your Sun sign or the sign just before or just after it. For births from 1930 to 2010 the split is almost even: about half have Mercury in the Sun sign and half in a neighbouring one.

When Mercury shares your Sun sign, the way you think and the way you are tend to line up, and people get what they expect when you speak. When Mercury sits in a neighbouring sign, your thinking has a different flavour from your core self: the steady Taurus who argues like a Gemini, the bold Aries who plans like a Pisces.

Mercury turns retrograde three times in most years, occasionally four, for about three weeks each time, so about one birth in five has it retrograde, and your result says so if you are one of them. The traditional reading is a mind that works by going back over things: reflective and thorough, sometimes slow to speak and quick to revise.

Mercury usually spends two to three weeks in a sign, and up to about ten weeks when a retrograde falls in it. It changes sign on about four days in a hundred. If yours is one of them and you have no birth time, the result gives both signs and the local minute Mercury crossed over; if you gave a time, it warns you when the crossing came within an hour of it.

Mercury is the quickest of the planets, covering up to about two degrees a day, so the calculation uses your exact birth moment whenever you have one. The time you give is converted to Universal Time with the historical time-zone rules of your birthplace, Mercury's apparent position comes from astronomy-engine, and it is placed in the tropical zodiac, in agreement with the Swiss Ephemeris to about an arcminute. What Mercury does in the rest of your chart, its house and its conversations with other planets, is on your whole chart, and the guide to reading a birth chart explains both.