The tenth house is the top of the chart. It begins at the MC, the highest point the zodiac reaches at the moment of birth, and covers profession, reputation, status and whatever strangers know you for. That description is standard and it is everywhere. Far less is written about the fact that the tenth house is a different size for different people, and the gap can be twofold.
A house is not a sign
A common mistake sounds like this: "my tenth house is in Taurus." A house is a sector, not a sign, and it has boundaries of its own. In Placidus, the most widely used system in Western astrology, house size depends on the latitude of birth and on the time of day.
We computed Placidus cusps across a full day at 15-minute steps for several latitudes. Here is what happened to the tenth house.
- Equator: 27.6° to 32.6°
- 30° latitude (Cairo): 23.2° to 34.9°
- 40° (Madrid): 21.1° to 36.6°
- 50° (Kyiv, Krakow, Frankfurt): 18.1° to 39.2°
- 60° (Oslo, Helsinki): 12.7° to 44.6°
- 65°: 6.6° to 50.8°
At the equator all twelve houses are nearly equal, with under five degrees between the largest and the smallest. At Kyiv latitude the tenth house is either narrower than 19 degrees or wider than 39, depending on the hour of birth. That is more than a twofold difference, and it decides how many planets land inside.
One moment, twelve different houses
Here is a concrete calculation: 21 March, 12:00 UTC, prime meridian, latitude 50°. House sizes from the first to the twelfth:
16.6° / 20.2° / 27.4° / 38.1° / 43.2° / 34.5° / 16.6° / 20.2° / 27.4° / 38.1° / 43.2° / 34.5°
The fifth house in this chart is almost three times the first. Opposite cusps always sit across from each other, which is why the second six repeat the first. And the tenth house here spans 38 degrees, so it necessarily covers two zodiac signs.
That is not an exception. By our calculation, at latitude 50° the tenth house covers two or more signs in 86.5% of moments in the day. At the equator, almost 98%. So the phrase "my tenth house is in sign X" is nearly always imprecise: there are two signs in it, and the only question is which one holds the MC and which one holds the far end.
Beyond the Arctic Circle the house cannot be computed
Above 66.5° of latitude Placidus is mathematically undefined: the point simply has no solution. Swiss Ephemeris quietly substitutes Porphyry in that case, and most calculators never mention it.
Our calculation for Tromsø (69.65°N) returns a warning inside the response itself: "Placidus is not defined for lat=69.65° (above 66.5°). Swiss Ephemeris substituted Porphyry." The cusps look entirely plausible: a tenth house of 5.7°, a largest house of 54.3°. Plausible, but from a different system.
If you were born in Murmansk, Tromsø, Rovaniemi or anywhere beyond the Arctic Circle, check which house system your calculator actually used. There will be a number either way; the label above it is often wrong.
What to actually read in the tenth house
House size is a technical detail, but a reading order follows from it.
- The sign on the MC. This is the main one: the way a person wants to be visible. It does not change with the house system, because the MC is an astronomical point rather than a division.
- The ruler of the MC and the house it sits in. Shows the area through which the career actually happens. Often the answer to "why am I not working in the field I trained for".
- Planets inside the house. Here size matters: a wide tenth house catches more planets, and not all of them will be in the MC sign.
- The second sign in the house. If the house spans two signs, the second one describes the later stretch of the professional path, not the beginning.
To build a chart with cusps and see the real boundaries of your tenth house, use a natal chart. An exact birth time is required: the MC moves roughly one degree every four minutes, so a half-hour error already shifts a planet from the ninth house into the tenth.
In short
The tenth house covers career, reputation and public status, and it begins at the MC. Its size in Placidus depends on latitude: 27 to 33 degrees at the equator, 18 to 39 at Kyiv latitude, 7 to 51 at the 65th parallel. Above 66.5° the system is undefined and the calculator quietly computes Porphyry instead.
Try calculating your chart for free on AstroWay and see how many degrees your tenth house takes up and how many signs fall inside it.