Birth chart with houses
One birth chart cast in four house systems side by side: Placidus, Whole Sign, Equal and Porphyry.
Plate 1. Birth details
Example chart: 15 June 1990, 14:30, London (an invented birth, not a real person)
Plate 2. Chart wheel
Select a planet on the wheel, or a row in a table.
Aspect lines
- Hard: dashed ink
- Flowing: solid blue
- Quincunx: dotted
- Conjunction: planets side by side, no line
Plate 3. House cusps in four systems
| House | Placidus | Whole Sign | Equal | Porphyry |
|---|---|---|---|---|
| House 1 | Libra11°14' | Libra0°00' | Libra11°14' | Libra11°14' |
| House 2 | Scorpio6°25' | Scorpio0°00' | Scorpio11°14' | Scorpio12°23' |
| House 3 | Sagittarius7°46' | Sagittarius0°00' | Sagittarius11°14' | Sagittarius13°32' |
| House 4 | Capricorn14°41' | Capricorn0°00' | Capricorn11°14' | Capricorn14°41' |
| House 5 | Aquarius20°01' | Aquarius0°00' | Aquarius11°14' | Aquarius13°32' |
| House 6 | Pisces18°47' | Pisces0°00' | Pisces11°14' | Pisces12°23' |
| House 7 | Aries11°14' | Aries0°00' | Aries11°14' | Aries11°14' |
| House 8 | Taurus6°25' | Taurus0°00' | Taurus11°14' | Taurus12°23' |
| House 9 | Gemini7°46' | Gemini0°00' | Gemini11°14' | Gemini13°32' |
| House 10 | Cancer14°41' | Cancer0°00' | Cancer11°14' | Cancer14°41' |
| House 11 | Leo20°01' | Leo0°00' | Leo11°14' | Leo13°32' |
| House 12 | Virgo18°47' | Virgo0°00' | Virgo11°14' | Virgo12°23' |
In this chart every cusp is in the same sign in all four systems; only the degrees differ. A cusp that is in a different sign from the Placidus cusp is marked “differs”.
Plate 4. Which house each planet falls in
| Body | Placidus | Whole Sign | Equal | Porphyry |
|---|---|---|---|---|
| Sun | 9 | 9 | 9 | 9 |
| Moondiffers between systems | 5 | 6 | 6 | 6 |
| Mercurydiffers between systems | 8 | 9 | 8 | 8 |
| Venus | 8 | 8 | 8 | 8 |
| Marsdiffers between systems | 6 | 7 | 6 | 6 |
| Jupiter | 10 | 10 | 10 | 10 |
| Saturn | 4 | 4 | 4 | 4 |
| Uranusdiffers between systems | 3 | 4 | 3 | 3 |
| Neptunediffers between systems | 3 | 4 | 4 | 3 |
| Pluto | 2 | 2 | 2 | 2 |
| North Nodediffers between systems | 4 | 5 | 4 | 4 |
6 of 11 placements change house between systems.
“differs” marks a planet that falls in a different house in at least one of the four systems. In those rows a house that is not the Placidus house is in bold and underlined.
Houses divide a birth chart into twelve areas of life, each beginning at a cusp. Placidus is the calculator’s default system; Whole Sign, Equal, and Porphyry divide the chart differently. The Ascendant and Midheaven usually stay fixed, while other cusps can move, so a planet may fall in a different house. These systems offer different symbolic ways to read a chart.
Houses mark areas of life
A birth chart has twelve houses, numbered from the 1st to the 12th. Each house is associated with an area of life, such as identity, close relationships, work, or private reflection. In astrology, these meanings are a symbolic language for reflection, not proof or a promise about what a person’s life will be like.
A house cusp is the boundary where a house begins. The zodiac sign on that boundary and any planets within a house can shape how astrologers read its themes. House systems set those boundaries in different ways, so the same planet may sit in a different house when the chart is viewed in another system.
Four ways to place cusps
Placidus, the default here, divides the space between the Ascendant and Midheaven using the time it takes points in the sky to rise and reach the meridian. Astrologers may choose it for this time based approach. It cannot be calculated near and beyond the polar circles, from about 67 degrees north or south. In those places, the calculator uses Porphyry and says so.
Whole Sign assigns one whole zodiac sign to each house. The sign containing the Ascendant becomes the 1st house, and the following signs take the next houses in order. This makes each house the same size, though the Ascendant can fall within the 1st house rather than mark its cusp. Some people choose it for its clear sign based structure.
Equal begins the 1st house at the Ascendant and makes each house the same size. The other cusps follow at equal intervals around the chart. The Midheaven remains a separate point, so it may fall in a house other than the 10th. People may choose Equal for its consistent divisions anchored to the Ascendant. Porphyry divides each quadrant between the Ascendant, Midheaven, Descendant, and IC into three equal parts. People may choose it for a straightforward division that keeps those angles as key boundaries.
Angles and changing house placements
In Placidus, Equal, and Porphyry, the Ascendant and Midheaven stay the same because they come from the birth time and place, not from the way the intervening houses are divided. Whole Sign also keeps those points in the chart, though it uses the Ascendant’s sign to set the 1st house and does not require the Ascendant itself to be a cusp. The remaining house boundaries can shift from system to system.
Because those boundaries move, a planet near a cusp may be placed in one house in Placidus and another in Whole Sign, Equal, or Porphyry. The planet’s sign and position do not change when you switch systems. Only its house placement changes, which can lead to a different symbolic emphasis in the reading. Comparing the views helps show how each system organizes the same chart.
Questions
Why does the calculator use Placidus as its default system?
Placidus is the calculator’s default, so charts begin with that house division. It is one common way to place cusps based on the sky’s motion through the day. The default is a starting point, not a ranking. You can compare it with Whole Sign, Equal, and Porphyry to see how each organizes the chart.
Can the same planet appear in two different houses?
Yes. A planet can fall in one house in Placidus and another in Whole Sign, Equal, or Porphyry because the systems place some cusps differently. Its zodiac sign and chart position remain the same. The house shift changes the area of life astrologers may emphasize when reading the planet symbolically.
Why is my Midheaven outside the tenth house?
The Midheaven is a chart point, while a house system determines where house boundaries fall. In Equal, Porphyry, or Placidus, the Midheaven does not have to mark the 10th house cusp. Whole Sign also treats it as a separate point. Its house placement can therefore vary with the system and chart.
What happens when Placidus cannot be calculated for my birthplace?
Near and beyond the polar circles, from about 67 degrees north or south, Placidus cannot be calculated. The calculator then uses Porphyry and says so. The birth chart still displays houses, but their cusps follow Porphyry’s divisions. You can compare the displayed system with other available house views.