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Mars sign calculator
Your Mars sign is the zodiac sign Mars occupied at the moment you were born. In Western astrology it describes your drive: how you go after what you want and how you handle anger and competition.
Your Mars sign is the zodiac sign Mars was in when you were born. Enter your birth date, time and place to get the sign, the exact degree, the house, and whether Mars was retrograde.
In Western astrology Mars describes drive: how you go after what you want, how you handle anger and competition, and where you spend effort. It is the planet of action, so its sign is read as the style of that action.
Unlike Mercury and Venus, Mars is not tied to the Sun. It can be in any sign whatever your birthday, and it usually spends about six to eight weeks in each one. Every two years or so Mars turns retrograde for two to two and a half months, and around those loops it can stay in a single sign for half a year.
How it is computed
Mars's geocentric longitude is computed from the JPL DE442 ephemeris for your birth instant, then placed in the Tropical zodiac and, with a birth time, in its Placidus house. Retrograde means Mars's longitude was decreasing at that instant, as seen from Earth.
Mars moves less than a degree a day, so the birth time only changes the sign if Mars crossed a sign boundary on your birth date. If you leave the time out, the calculator uses noon and tells you whether that happened and roughly when.
Common questions
- Can I find my Mars sign without a birth time?
- Yes. Mars moves less than a degree a day, so it changes sign on only a handful of days in a year. The calculator uses noon when the time is unknown and tells you if Mars changed sign on your birth date. The house is the one thing that needs a time.
- What does my Mars sign mean?
- It describes the way you act on a want: fast or slow, direct or strategic, alone or with others. The sign gives that drive a style, the house says where in life it shows, and aspects from other planets add pressure or support.
- What does a retrograde Mars at birth mean?
- Mars appears to move backward for two to two and a half months every two years or so. Astrologers read a retrograde natal Mars as drive that is turned inward first: anger and ambition that are thought through, held back, or acted on later than other people expect.
- Which Mars signs are strongest?
- In traditional astrology Mars is at home in Aries and Scorpio, the signs it rules, and exalted in Capricorn. It is in detriment in Libra and Taurus and in fall in Cancer. These labels describe how easily Mars works in a sign, not how strong the person is.
- How accurate is this calculator?
- Positions come from NASA JPL's DE442 ephemeris via Skyfield. In a published check of 870 positions against the Swiss Ephemeris, the median difference was 0.17 arcseconds and the largest was 26.7 arcseconds, under half an arc-minute; the two never disagreed on a zodiac sign or a whole degree. That check compared planet positions, not house cusps: your Ascendant and houses depend on your birth time and place, and a birth time a few minutes off matters far more than the ephemeris. The method and the full data table are in our ephemeris accuracy study.
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Positions are computed from the JPL DE442 ephemeris in the Tropical zodiac with Placidus houses. Readings are educational, drafted from the computed factors and edited by the Shymea team; they are not the work of a named practising astrologer and are not medical, legal or financial advice. See the editorial policy.
