Which House System Should You Use in Astrology?
If you’ve ever explored astrology, you’ve probably noticed there’s more than one way to divide your birth chart into houses, and that can be confusing. From Placidus to Equal, Campanus to Whole Sign, there are many house systems to choose from. So, how do you decide which one is right for you?
Either if you're team Placidus, curious about Whole Sign, or just found out about Porphyry, you’re not alone. Picking a house system can feel overwhelming, but it doesn’t have to be! In this diary entry, we will break down together the most popular house systems, explain their differences, and help you figure out which system fits you the best.
What are Houses in Astrology Anyway?
Before we jump into the systems, a quick note: astrology charts are divided into 12 houses, each representing different areas of life, like career, relationships, home, and more. The way the sky is sliced into these houses varies depending on the system used, and this can affect the interpretation of your chart.
The Most Common House Systems Explained
Choosing the ‘right’ house system depends on your astrological approach either depending on what type of astrology do you prefer to study. Also, please keep in mind that there are no rules set in stone with astrology and there is no ‘right’ and ‘wrong’ just like there is no ‘good’ or ‘bad’. Usually through practice, you get in sync with what matches your approach best through time.
1. Placidus (Time-Based and Popular)
Origin: the time-based Placidus system was first formulated in the early 17th century by the Italian astronomer Giovanni Antonio Magini (1555–1617) and later published by the monk Placidus de Titis (1603–1668). It is named after Placidus, but Magini was the original inventor.
How it works: it’s a system that divides the sky based on time. It splits the time it takes for the Sun (or a point on the ecliptic) to move from the Ascendant to the Midheaven into three equal parts. It does the same for the time from the Descendant to the Imum Coeli. The house boundaries (cusps) are placed where these time divisions occur along those arcs.
Features: reflects the Earth’s rotation and diurnal motion, making it highly sensitive to exact birth time and location.
Who uses it: The most widely used house system in modern Western astrology, especially for psychological and natal chart readings.
It’s most likely a match for: those wanting a system deeply tied to personal timing and real-world movement, offering detail and depth in house placements.
Limitations: can be problematic at extreme latitudes (e.g., near the poles) where time distortion affects calculation as due to mathematical reasons, Placidus houses cannot be calculated for regions beyond the polar circles.
2. Equal Houses (Simple and Straightforward)
Origin: likely Greco-Roman, pre-dates Placidus.
How it works: starts the 1st house at the exact degree of the Ascendant; each house is 0-29°, regardless of sign boundaries.
Features: even spacing, but keeps Ascendant as starting point (unlike Whole Sign).
Who uses it: still used by many modern Western astrologers, especially for those born in high latitudes.
Most likely a match for: those seeking balance between geometry and symbolism, or working with uncertain birth times.
Limitations: can feel too uniform, lacking the dynamic detail quadrant systems provide for time-based events and depth.
3. Whole Sign Houses (Ancient and Pure Zodiac Focus)
Origin: Ancient Greece (Hellenistic period)
Timeframe: ~2nd century BCE
Creator: unknown; widely used by early astrologers like Dorotheus, Valens, and Ptolemy
How it works: each sign = one house. The entire sign that contains the Ascendant becomes the 1st house, and so on in 0-29° steps.
Features: all houses are exactly 0-29°; clean and symbolic.
Who uses it: widely revived by Hellenistic astrologers and many modern traditionalists.
It’s most likely a match for: those wanting clean symbolism and fewer complications from house distortion.
Limitations: can feel too detached from the exact degree of the Ascendant, since house cusps always start at 0° of each sign so this may reduce precision in interpreting planets near house cusps.
4. Campanus (Spatial, Prime Vertical Division)
Origin: from 13th-century mathematician Campanus of Novara.
How it works: the celestial sphere is divided into 3D space from the ASC–DC and MC–IC axes.
Features: geometry-based, highly angular system.
Who uses it: mostly horary and mundane astrologers
Best for: those wanting a structured yet symbolic system.
Limitations: can produce house distortion at extreme latitudes.
5. Koch (Latitude Sensitive)
Origin: named for Walter Koch (1895–1970), but actually devised by Friedrich Zanzinger (1913–1967) and Heinz Specht (b. 1925) in Germany. Era – 1930s (mid-20th century).
How it works: The Koch house system divides the sky based on how long the Midheaven (MC) degree has been above the horizon on your birth day. It looks at the time the MC has spent rising, then finds the point where the Ascendant was after one-third of that time for the 12th house cusp, and after two-thirds of that time for the 11th house cusp. The 9th and 8th house cusps work similarly, using the Descendant’s position after one-third and two-thirds of that time.
The Koch system uses the movement of the MC at your birth to split the houses. Like Placidus, it’s based on how the sky moves with time.Features: reflects inner experience, especially for psychological astrology.
Who uses it: favored by astrologers who calculate progressions, solar arc directions, and timing techniques because of that sensitivity.
Most likely a match if: you are highly focusing on timing and static houses like traditional ones are too static for you.
Limitations: fails at high latitudes (above ~60°) just like Placidus.
6. Porphyry (Angle-Based)
Πορφύριος, romanized: Porphýrios; c. 234 – c. AD 305) is also known as an opponent of Christianity and defender of Paganism.
Origin: attributed to 3rd-century philosopher-astrologer Porphyry of Tyre.
How it works: one of the earliest quadrant-based house systems in astrology, that uses the four major angles:
Ascendant (ASC)
Descendant (DSC)
Midheaven (MC)
Imum Coeli (IC)
Each quadrant is divided into 3 equal parts → results in 12 unequal houses.
Features: simple yet angle-based
Who uses it: both modern and traditional astrologers, and modern traditionalists as well
Most likely a match if: if you want a balanced, middle-ground approach between ancient and modern systems.
Limitations: less nuanced in fast-moving charts.
7. Regiomontanus (Equatorial Split)Origin: based on a 12th-century scheme by the Spanish Jewish astrologer Abraham ibn Ezra (d. 1167); system named after Johannes Regiomontanus (1436–1476) who popularized it in the 15th century.
How it works: The Regiomontanus system splits the celestial equator into 12 equal parts of 30° each. Then, from each point, it draws a line straight up and down to meet the zodiac. Where these lines cross the zodiac are the house boundaries. This makes houses of different sizes, like cutting a pie into uneven slices.
Features: one of the earliest quadrant systems, balancing mathematical precision with practical use; houses vary in size depending on latitude and birth time.
Who uses it: favored by traditional and classical astrologers, especially in horary and electional astrology, and popular in medieval and Renaissance Europe.
It’s mostly a match for: those who appreciate classical astrology methods and want a system that reflects the Earth’s rotation and zodiac placement with historical roots.
Limitations: House sizes can vary widely.
How to Choose a House System That Works for You
The truth is, there’s no ‘one size fits it all’ system and in fact there never was and never will be. Choosing a house system depends on:
Your astrological goals – for example psychological insight vs spiritual evolution vs timing and prediction
Your location – high latitudes distort many systems
Your chart resonance – which interpretation actually feels mostly in sync with your approach?
All in all, you’re not stuck with one system forever. The ‘best’ astrologers are curious experimenters that think out of the box and seek innovation. 😉
Many Astrologers Use Multiple Systems
Some astrologers use Whole Sign for natal, Placidus for timing, and Porphyry or Campanus for horary or spiritual readings. Nothing is set in stone. I personally use Whole Sign primarily, as tracking annual profections shown me the eerily high time based accuracy throughout lifetime tracking. But I also use play and test Placidus, Koch, and Porphyry for tracking transits and progressions.
It’s Your Sky. Slice It Your Way.
Choosing a house system isn’t about finding the “correct” one, it’s about finding what resonates with your chart, your path, and your practice! Don’t be afraid to play with different systems and trust what feels aligned.
After all, astrology is a language. And like any language, you get to choose your accent.
Until the next diary entry,
xx Ang
