Mars Sign Calculator

What Your Mars Sign Describes

Mars describes drive: how you go after what you want, how you handle conflict, what makes you angry and how you use your physical energy. An Aries Mars may act first and think later; a Libra Mars may weigh every side before moving and fight hardest for fairness. Read more about Mars in astrology.

How the Mars Sign Is Calculated

Mars takes about two years to circle the zodiac and spends about six to seven weeks in a sign, 55 days on average from 1900 to 2060. Roughly every 26 months it turns retrograde for ten to eleven weeks, which can hold it in one sign for months: the longest stay in that range lasted 235 days, in Virgo.

Unlike Mercury and Venus, Mars can sit in any sign relative to your Sun. The calculator finds its apparent geocentric longitude at your birth instant, and whether it was retrograde.

Why Birth Time Matters

Between 1900 and 2060, Mars changed sign on about 2% of days, roughly 1 day in 53. If your birthday is one of them, the sign depends on the hour you were born. Without a time, the calculator checks every hour of your birth date (in every time zone, if you leave out the place) and shows each sign Mars could have held.

With your birth time and place, the result also gives the exact degree and the house, the area of life where this placement works.

How Accurate Is It?

Positions come from Selfgazer's astrology engine, the same one that draws the chart in your astro room: VSOP87 planetary theory through Astronomy Engine, with Chiron from Swiss Ephemeris tables. Tested against the Swiss Ephemeris, planets agree to within half an arcminute and house cusps to within a tenth of an arcminute. Your local birth time is converted with your birthplace's historical time zone rules, including past daylight saving changes. Everything is calculated in your browser, and nothing you enter is stored.