Free Stellium Calculator

A stellium is a group of planets that an astrologer treats as a concentration in a chart. Definitions differ: the number of planets, the bodies included and whether conjunctions are required can all change whether a group qualifies.

This calculator checks a specific definition: at least three or at least four of the ten core bodies sharing a tropical sign or an astrological house. It does not require conjunctions or a personal planet. Your result compares both definitions and lists the planets in each group.

• 3+ rule: three or more counted bodies share one sign or house.
• 4+ rule: four or more. A group of exactly three no longer qualifies; its positions have not changed.

Requiring four planets is stricter, but neither definition is universal. We also do not require Sun, Moon, Mercury, Venus or Mars in the group. If none is present, the details say so without excluding the group.

Same sign does not mean conjunct

Imagine three planets at 1°, 15° and 29° of the same sign. They meet our 3+ rule despite being far apart. This calculator groups planets by sign or house, not by how close together they are.

Planets can also be close across a sign boundary and therefore belong to different sign groups. That is another reason a conjunction-based tool may disagree with a sign-count tool.

Sun and Moon count under this astrological convention, although astronomically they are a star and a natural satellite. Every body counts once within a group.

Other points can be listed when they share the group’s sign or house. This does not imply close angular distance or a conjunction. ASC and MC appear with sign groups only. Juno, Vesta and Pallas are outside the count and are not listed as contextual points here.

A sign group collects planets with the same zodiac sign. A house group collects planets with the same house number. A shared sign does not guarantee a shared house; the local birth chart and house system determine that second grouping.

The same planets can form both a sign stellium and a house stellium. When this happens, your result points it out. Groups can also share only some planets; compare their lists to see which.

“No match under 4+” means no group has at least four planets. “Not calculated” means we could not calculate your houses, not that you have no house stellium.

These example charts use Swiss Ephemeris, New York coordinates 40.7128, −74.006 and the tropical zodiac. They do not belong to real people. You can enter the dates and times below to compare results; the coordinates for your selected city may differ slightly.

Compare the members of the timed August example: its sign and house rows describe the same set of planets. Removing the birth time removes the house check; it does not establish that the person has no house stellium. The noon sample is not a check of every possible birth time that day.

We can check sign groups at a reference time: noon in the birthplace’s timezone, or noon UTC if the place is omitted. The sign groups are estimates. We do not calculate houses.

A sign change during the day can alter a group’s count. The Moon is particularly time-sensitive. If one member of an exactly three-planet group occupies another sign at your actual birth time, the group may no longer meet the 3+ rule.

We do not check every possible birth time that day, so the group may differ at your actual birth time. Houses require both birth time and place; we leave them out when either is unknown.

We use your birthplace to determine the timezone and calculate planetary positions with Swiss Ephemeris in the tropical zodiac. With birth time and place, we also calculate houses. We normally use Placidus; if a different house system is needed, its name appears in your result.

Your result lists planets sharing a sign and, when houses are available, planets sharing a house. Compare the 3-planet and 4-planet definitions without entering your details again.

Your birth details are sent to our server for calculation and saved in your browser so you can reuse them across tools. Our usage statistics do not include your birth details or chart results. Read the privacy policy.

Astrological interpretations associate a sign group with a style of expression and a house group with a life area. Read the actual planets together rather than treating the group label as a complete personality description. The result includes a general sign or house interpretation, not a scientifically validated prediction.

A chart does not need a stellium to have areas of emphasis. The dominant planet calculator asks a different question about scored planetary emphasis. You can use it whether or not any stellium group meets your chosen rule.