Astrology House Systems: A Guide to Choosing the Best One for You
You might already know the twelve houses in your birth chart, each corresponding to a different aspect of your life. You may have also noticed your favorite astrologer expressing preference for a particular house system—in other words, the method they choose to divide the chart into houses, which can impact house sizes, zodiac ruler-ship, and more.
My early astrology mentors taught me to use the “Placidus” system unless I had a good reason to use another. I didn’t question this, until the day I whimsically decided to calculate my birth chart with the “Equal” house system. To my dismay, my Twelfth House Sun was now living in the Eleventh House. “Oh no,” I thought, fearing I might never understand myself.
With experience, I’ve learned that you can find answers using any house system. That said, choosing a different house system might help you rephrase an existential question, providing paths that other systems couldn’t. And that, as my teachers suggested, might be a very good reason to explore new ones.
How Does the House System Affect Your Chart, Anyway?
First, here’s what the house system won’t change:
Your birth chart always consists of twelve houses.
Your ascendant, or the sign that’s rising on the eastern horizon when you were born, always remains the same.
The major differences to your birth chart are the locations of the house cusps. Cusps are doors, or starting boundaries, of each house. Across house systems, cusps can occur in different zodiac signs and form houses of varying sizes.
Even a few small differences between systems can have you questioning your whole identity. But just as we can benefit from viewing ourselves through multiple lenses, you might find that some house systems are better suited for certain contexts or problems.
Popular House Systems Over Time
The ways of dividing the zodiac into houses have progressed as our tools and theories about the universe have. A system isn’t inherently better because it’s older or newer, but its place of origin does shape its features and common uses today.
Ancient Observations
The oldest systems are the simplest. Even without much technology, astrologers could observe that star positions change throughout the seasons, days, and nights. For example, the Sun and zodiac constellations appear to make a ring around the Earth over 24 hours. And over 365 days, the path of that full circle seems to return to its original position in the sky.
The two house systems below divide that zodiac ring into twelve even 30-degree sections, reflecting the cultural values of balance and beauty in Ancient Greece.
Whole Sign
In the Whole Sign system, the First House cusp is defined as the beginning (0 degrees) of the rising zodiac sign. This is always true, even though your ascendant may have risen somewhere in the middle of the sign.
Key Features: All houses are the same size, and each is associated with exactly one zodiac sign.
Origin: Documented in ancient India as well as Hellenistic Greece by the first century BCE, it’s also popular in modern astrology.
Use Cases: Use this system for its accessibility, which makes it easy to understand astrology principles. Birthplace also doesn’t affect the consistency of the house cusps. Great for birth analysis, but not as precise for analyzing the timing of later life events.
Equal
The Equal house system divisions differ from Whole Sign because the First House cusp begins at the exact degree of the ascendant.
Key Features: All houses are the same size, but each cusp starts at the ascendant degree within each zodiac sign. So, unless your ascendant appeared at exactly 0 degrees (unlikely), each house contains two zodiac signs.
Origin: Also traced to Hellenistic Greece in the first century BCE, there’s debate about whether this could be the oldest house system.
Use Cases: Use this system because it’s simple, consistent no matter where you’re born, and more individualized than Whole Sign. However, like Whole Sign, It’s not as precise for understanding current life themes or predicting events.
Earth-Centered Middle Ages
Aristotle’s theory of an Earth-centered universe dominated Medieval Europe. Therefore, it’s no surprise that the many Medieval house systems, including Campanus, were based on different ways of dividing the space around Earth.
Campanus
The Campanus method starts by dividing an imagined sphere around you into twelve equal sections, emphasizing your location on Earth as an observer of the sky. The actual cusps result when you project these sections onto the plane of Earth’s tilted orbit.
Key Features: The First House begins at the exact degree of the ascendant, but houses are typically unequal sizes and may span two or more zodiac signs.
Origin: Named after Campanus of Novara in 13th-century Italy, this system was likely used earlier by Persian scholars.
Use Cases: Since Campanus emphasizes the birthplace and the Earth, it’s often used for “worldly” activities. Examples include predicting sports outcomes and mundane astrology, which deals with political events.
Time and the Renaissance
Finally, the Copernican Revolution generated a widespread acceptance of a Sun-centered solar system. Given the deeper understanding of how Earth’s movements affect our experience of time, house systems of the Renaissance prioritize time measurements.
Placidus
With Placidus, you calculate house cusps by measuring time intervals as your ascendant degree rises to the highest point in the sky (your Tenth House cusp) and then back to the horizon (your Seventh House cusp).
Key Features: The First House cusp occurs at the exact degree; houses have unequal sizes and can contain two or more zodiac signs.
Origin: The most commonly used house system today, Placidus is an old system, popularized in 17th-century Italy by an Olivetan monk of the same name.
Use Cases: Popular for psychological astronomy, this system helps address questions of the mind and soul. It’s great for uncovering the specific timing of major life phases.
Koch
In some high latitudes (very North or South) at certain times, the Sun might never rise or set. Without getting into too much math, these extreme examples illustrate why time-based systems can break down in latitudes above about 66 degrees.
The Koch house system still uses timing to identify house cusps, but it makes adjustments to counteract measurement problems at high latitudes.
Key Features: This house system looks like Placidus, but spatial adjustments make house cusps differ slightly.
Origin: Devised in 1960 by the German astrologer Dr. Walter Koch, the system is still popular in Germany.
Use Cases: It’s good for everything Placidus is good for, especially for people born closer to the poles. However, distortions can still happen.
Which System Do Professional Astrologers Use?
Placidus is the most common and Whole Sign quite trendy, but every astrologer has a preference for a good reason:
Chani Nicholas uses Whole Sign for its “visual elegance and simplicity.”
Jessica Lanyadoo, who’s especially focused on human relationships and events, uses Campanus.
Anne Whitaker switched to Equal after years of using Placidus because she prefers giving equal weight to the archetypes associated with each house.
Steven Forrest likes Placidus because it emphasizes that space and time are intertwined, and it has proven results for his psychology clients.
Then again, many astrologers, like April Elliott Kent who uses Koch, say they simply prefer the system their teachers used—a perfectly fine reason, too!
Which House System Should You Follow?
Most astrologers explore all house systems to uncover what feels true to their realities. Still, there are a few basic questions you can consider to help you decide your best fit:
What do you want to prioritize in your practice? If you want to privilege symmetry and ease, Whole Sign and Equal are simple systems with evenly sized houses. But for deeper psychological exploration, for instance, Placidus might prevail.
What problem are you trying to solve? Campanus could be a good fit for a worldly matter, such as analyzing the influences acting on a political election or deciding whether to take a risk. But the time-based Placidus and Koch systems could be better for understanding the lengths and themes of your life phases.
How much do you want location to matter? You might prefer a consistent approach that’s meaningful regardless of the birthplace of the person you’re reading, in which case Whole Sign or Equal is a good choice. However, location is important to identity for many, who might then prefer space-based or time-based systems.
In astrology, a house system is an organization strategy. No matter the system you choose, its purpose is to help you find what you need from a chart. Just as we’d never dictate how someone should organize their home, why should there be only one true way to divide the sky?