Whole sign houses give each zodiac sign exactly one house of 30 degrees, starting with your rising sign. Placidus houses start at the exact ascendant degree and are cut by time and latitude, so they come out uneven. Your rising sign is the same in both, but a planet near a boundary can land in a different house, and the later your ascendant falls in its sign, the more planets shift. Neither app is necessarily buggy. Pick the system your reading method was built for and stay with it.
You enter the same birth details into two apps and Saturn is in the 10th house in one and the 9th in the other. The usual reaction is to decide one of them has a bug, and then to stop trusting both. It is a fair reaction, and it is usually wrong.
A house system is the method that divides a birth chart into 12 houses, and Placidus and whole sign are two of the most widely used. They agree on where the planets are and on your rising sign. They disagree on where each house begins and ends.
What is the whole sign house system?
In whole sign houses, your rising sign is the 1st house, the next sign is the 2nd, and so on around the zodiac. Every house is exactly one sign, or 30 degrees. The exact degree of your ascendant does not move any boundary.
Most traditional Vedic reading assumes this setup, and many Vedic apps draw charts this way by default. It is also the easiest system to check by hand: find the rising sign and count signs forward to get every house. Our rising sign guide covers how that first sign is found.
What is the Placidus house system?
Placidus is a time-based system. It starts the 1st house at the exact ascendant degree and places the other cusps by dividing the time a point takes to travel from the horizon to the meridian into equal thirds. Because that depends on your latitude, the houses come out unequal in size.
It is the default in many Western programs, and KP astrology borrows its cusps, as the KP sub-lord post describes. At Indian latitudes the unevenness is moderate. Far enough north, above roughly 66.5 degrees, Placidus cannot be computed for some birth times at all, which is one reason other systems exist.
One reassuring detail: the ascendant itself is the same in every house system, because it is a point on the horizon and does not depend on how you slice the houses.
Why can the same planet land in two different houses?
The boundaries sit in different places. Whole sign puts a boundary at 0 degrees of every sign, while cusp-based systems measure from your exact ascendant degree. A planet caught between the two boundaries changes house.
Take an ascendant of 28 degrees Libra with Mars at 5 degrees Scorpio. In whole sign houses Libra is the 1st and Scorpio is the 2nd, so Mars is in the 2nd. In an equal-house system the 1st house runs from 28 degrees Libra to 28 degrees Scorpio, so Mars is in the 1st. Placidus also measures its 1st house from the ascendant degree, and its 1st house is far wider than 7 degrees, so it puts Mars in the 1st too.
You can estimate how much will move. The share of planets that shift is roughly your ascendant degree divided by 30. With an ascendant at 2 degrees of its sign almost nothing changes. With one at 27 degrees, most planets in the first 27 degrees of their signs step back a house in a cusp-based system.
Which house system does Vedic astrology use?
Most traditional Vedic practice reads the chart in whole sign houses. KP astrology is the main exception and uses Placidus cusps. Some practitioners also look at a bhava chalit view, which re-sorts planets using cusp-based houses, next to the main chart.
| System | House 1 starts at | House size | Common in |
|---|---|---|---|
| Whole sign | 0° of the rising sign | Always 30° | Traditional Vedic charts |
| Equal house | Exact ascendant degree | Always 30° | Some Vedic and Western software |
| Placidus | Exact ascendant degree | Uneven, varies with latitude | KP astrology, many Western programs |
Which house system should you trust?
Neither wins on accuracy, because a house system is a convention for slicing the sky and not a measurement of it. What matters is consistency: use the interpretation rules that were written for the system you are looking at.
That is where people get tripped up. Rules that count aspects from sign to sign assume signs and houses are the same thing, and KP rules assume Placidus cusps and sub-lords. Borrowing a KP verdict and applying it to a whole sign chart, or the reverse, mixes two methods and produces confident nonsense.
A practical check: look for the house system the app names, usually in the settings or beside the chart. If it names none, compare the ascendant degree across apps. A late degree explains most disagreements, and a shaky birth time makes it worse, since the ascendant moves roughly one degree every four minutes. The birth chart accuracy guide covers that side. And if a planet changing house between two apps has you worried about your life, take a breath: it is a drawing choice, and astrology is not a substitute for professional help when real distress is involved.
See your chart read in plain language
Vedikks reads your birth chart, dashas, transits and the current panchang together, then answers in plain language. Ask about any placement and get an answer built on your own chart, not a sun-sign template.
Get my chart, freeQuick answers
What is the difference between Placidus and whole sign houses?
Whole sign houses give each zodiac sign exactly one house of 30 degrees, starting with the rising sign. Placidus houses start at the exact ascendant degree and are cut by time, so they come out uneven in size. The rising sign is identical in both, but planets near a boundary can change house.
Which house system does Vedic astrology use?
Most traditional Vedic reading uses whole sign houses, and many Vedic apps draw charts that way by default. KP astrology is the main exception, because it uses Placidus cusps. Some practitioners also check an equal-house or bhava chalit view alongside the main chart.
Why does my planet show in a different house in another app?
The two apps are most likely using different house systems. A planet changes house when it sits between the whole sign boundary at 0 degrees of a sign and the cusp that another system draws from your exact ascendant degree. A later ascendant degree means more planets shift.