♂ Free Mars Sign Calculator
Umbriel's free Mars sign calculator finds your natal Mars (its sign, exact degree and house) from your birth date, time and place.
Runs in your browser.
4420+ people cast their chart here in the last 30 days.
No account, no email. Mars spends around about eight weeks on average in a sign, so the date alone is usually enough to place it.
- What you'll needBirth date (time and place for the house)
- What you getYour Mars sign and exact degree, the house it falls in, whether it was retrograde, and every aspect it makes
- CostFree, no account required
What a Mars sign is
Your Mars sign is where Mars stood at your birth. It is traditionally associated with drive, appetite, anger and effort: how you go after things, what you do with frustration, the style of your push. Where Venus is what attracts you, Mars is what you do about it.
Mars is the first of the planets outside Earth's orbit, which changes its rhythm completely. It takes about two years to circle the zodiac, roughly about eight weeks per sign on average, but every two years or so it turns retrograde for two to two and a half months, and a sign caught by a retrograde can hold Mars for six or seven months. If your Mars is in a sign it lingered in, it will be sharing that placement with an unusually large cohort.
It is the placement most often read badly. Mars in a sign is not a verdict about how angry someone is; it is a description of a style of acting: direct or oblique, fast or sustained, open or withheld. The house it falls in usually says more about where that shows up than the sign says about what it looks like.
How Umbriel computes it
This tool places Mars in a sign and degree, and says whether it was moving backward, from your birth date and time. Mars is calculated from orbital elements: they are advanced to your birth moment, Kepler's equation for Mars's orbit is solved by repeated refinement, the position is found as seen from the Sun, and the Sun's position as seen from Earth is added to give the direction as seen from Earth. The sign is the tropical longitude divided into 30 degree sections, or the sidereal one if your chart is set that way, with the ayanamsa subtracted. Retrograde is decided by comparing Mars's longitude half a day before and half a day after your birth moment; if it is falling, Mars is marked retrograde. The house needs a birth time and place, because houses are measured from the Ascendant, and without a time Umbriel gives no house. For accuracy, the accuracy page reports Mercury, Venus and Mars against published ingress dates at under 0.2 degrees, which is not a JPL comparison as for the outer planets. Mars covers 0.524 degrees a day on average in the code, so 0.2 degrees is under half a day of its motion, and the sign is only in doubt if Mars entered or left a sign within about that time of your birth. Because Mars moves that slowly, an unknown birth time rarely changes the sign, but it does remove the house.
What's in your result
- Sign and exact degreeTo the degree and minute, so a Mars near a boundary is visible, not rounded away.
- The house it falls inWhere the drive tends to be spent. Needs your birth time.
- Retrograde or directWhether Mars was retrograde at your birth, with its speed, including the crawl either side of a station.
- Every aspect it makesEach contact with its exact orb, applying or separating.
- Its dignityWhether Mars sits in a sign it traditionally rules, is exalted in, or is uncomfortable in: the classical layer most calculators skip.
- The sign's rulerWhere Mars's dispositor sits, and what that says about how the drive gets directed.
Don’t know your birth time?
Know it roughly? Give the time and say where it came from (a certificate, a parent’s memory, or something rough like “early morning”), and your chart tells you what could change within that window.
Don’t know it at all? Umbriel does not fill the gap with a guess. Tick “I don’t know the time at all” and it checks your whole birthday, hour by hour, then tells you two things: which placements are the same whatever time you were born, as exact as they would be if you knew the minute, and which are down to two signs, both named, so you know what a parent’s memory would settle.
The Ascendant, the Midheaven and the houses are left out rather than approximated. A birth time is the one thing they cannot be computed without, and an approximate Rising sign that looks exact is worse than no Rising sign at all.
Common questions
Can I find my Mars sign without a birth time?
Yes, in nearly every case. Mars stays in a sign for about eight weeks on average, so the date settles it unless you were born within a day of an ingress. The house needs a time, and Umbriel leaves it blank without one rather than casting noon and calling it yours.
What does the Mars sign mean?
It is traditionally read for drive and assertion: how you pursue what you want, and what you do with anger and frustration. It describes a style, not an intensity, which is the distinction most popular writing on Mars loses.
What does a retrograde Mars mean in a birth chart?
Mars turns retrograde for about two months every two years, so roughly nine percent of charts have it. It is traditionally read as drive that turns inward before it turns outward: energy that is held, redirected or reconsidered, not discharged immediately. It is common enough that treating it as a problem says more about the reading than the chart.
Why do two websites give me different Mars signs?
Almost always a birth close to an ingress combined with a time-zone difference. Umbriel takes the zone from your birth city on your birth date, with that year's daylight-saving rule, which is the usual point of failure.
Is this Mars sign calculator free?
Yes: sign, degree, house, retrograde status, dignity and aspects, with no account and no email.
What if I don’t know my birth time?
Umbriel checks your whole birthday hour by hour and separates what is certain from what is not. Placements that are the same whatever time you were born are shown as exact. Placements that changed sign during the day are shown as two named signs, so you know what a parent's memory would settle. The Ascendant, Midheaven and houses are left out rather than approximated. They cannot be computed without a time, and an approximate Rising sign that looks exact is worse than none.
Do I need an account or an email address?
No. There is no sign-up, no email capture and no free trial. Enter your details and the result is drawn in your own browser.
Go deeper
Every one of these is a page in its own right, written out one at a time.
Related free tools
Umbriel offers every system here as a set of prompts to think with, never as a statement of fact about who you are. Take what's useful, leave the rest.