The planet of thought and speech
In astrology, Mercury is linked with the mind: how you take in information, solve problems, speak, write and learn. Astrologers read the Mercury sign as a description of thinking style rather than intelligence.
An earth Mercury is often described as practical and step by step. An air Mercury is associated with quick connections and conversation, a fire Mercury with bold, fast opinions, and a water Mercury with thinking colored by memory and mood.
Only three signs are possible
Mercury is the planet closest to the Sun, and from Earth it never appears more than about 28 degrees away from it. That is less than one full sign.
So your Mercury is always in your sun sign or in one of the two signs right next to it. A Taurus, for instance, has Mercury in Aries, Taurus or Gemini. Astrologers find this useful: a Mercury in the sign before the Sun is often read as a mind that looks back, and one in the sign after as a mind that looks ahead.
Retrograde stations and stop-and-start motion
Mercury turns retrograde three to four times a year for about three weeks at a time. During those periods it can drift back into the previous sign and then return, so the dates in our table sometimes show Mercury entering the same sign twice within a few weeks.
A natal Mercury retrograde is common, appearing in a sizable share of charts. Astrologers often read it as a reflective, revising mind that prefers to think something over before speaking. The Mercury retrograde page lists the upcoming periods.
The Mercury table and how to use it
Below the calculator we include a full list of Mercury sign periods from 1950 to 2030, computed with Astronomy Engine and shown in UTC.
Because Mercury moves fast for a planet, some sign changes land late in the evening in US time. If your birth date matches a change in the table, run the calculator with your birth time to see which side you fall on.
Reading Mercury with its neighbors
Since Mercury sits so close to the Sun, it often shares a sign with it. Astrologers then read thinking and identity as tightly bound. When Mercury sits in a different element from the Sun, they read a more noticeable gap between how a person feels and how they explain it.
Compare it with your Sun on the sun sign calculator, or see the whole picture in your birth chart.