Astrology basics
Placidus vs Whole Sign Houses: Which Should You Use?
If you have ever generated your birth chart on two different sites and noticed the house cusps don't match, you're not imagining it. Your planets and signs stay the same — but the house system can place those planets in different houses. The two most common systems are Whole Sign and Placidus, and this guide explains both in plain language.
Follow along with your own chart. Our birth chart calculator lets you switch between Whole Sign and Placidus live, so you can see exactly how your cusps change.
First: what are houses?
The zodiac signs describe how a planet expresses; the twelve houses describe where in life it shows up — self, money, relationships, career, and so on. A house system is simply the method used to divide the wheel into those twelve slices, starting from your Ascendant.
Whole Sign houses
The oldest system, used in Hellenistic and much of traditional and modern astrology. The rule is beautifully simple: each whole sign is one house. If your Ascendant is in Leo, then the entire sign of Leo is your 1st house, Virgo is your 2nd, Libra your 3rd, and so on. Every cusp sits at 0° of a sign.
- Pros: clean, easy to learn, works at every latitude, and keeps each sign intact.
- Trade-off: your Midheaven (career point) isn't always the 10th-house cusp — it can fall in the 9th, 10th or 11th.
Placidus houses
The most popular system in modern Western astrology. Instead of using whole signs, Placidus divides the sky by time — how long a degree takes to rise — so the houses are usually unequal in size and each cusp falls at a specific degree. Your Ascendant is the 1st cusp and your Midheaven is always the 10th.
- Pros: puts the angles (Ascendant and Midheaven) exactly on the 1st and 10th cusps, which many astrologers prefer for timing and prediction.
- Trade-off: distorts badly at high latitudes (near the poles) and can spread one sign across two or three houses.
The key difference in one line
Whole Sign: one sign = one house, every cusp at 0°. Placidus: houses split by time, cusps at real degrees, angles fixed to the 1st and 10th. Your planets don't move — but which house they land in can shift between the two.
So which should you use?
There's no single "correct" answer — it's a tradition, not a fact. A simple guide:
- New to astrology? Start with Whole Sign. It's simpler and keeps signs and houses aligned.
- Doing predictive work or following a Western teacher? Placidus is the modern default and pins your angles precisely.
- Born at a high latitude? Whole Sign stays reliable where Placidus can get strange.
The best way to decide is to look at both and see which describes your life more accurately.
Try both on your own chart
Generate your chart free with our birth chart calculator and toggle between Whole Sign and Placidus to compare your house cusps side by side. New to the pieces of a chart? Start with how to read your birth chart.
Run an astrology site? The same calculator — with both house systems and a visitor toggle — embeds on your own WordPress, Shopify or Wix site under your brand as an astrology widget.