Birth Time Lab

Free tool

Astrology Houses Calculator (Placidus)

Enter your birth date, time and place to get your twelve house cusps in the system and the house each planet falls in. We also list the planets that would change house if your time were 30 minutes earlier or later.

Narrow it down with your life events

A calculator needs a time. Our report works the other way round: it tests the possible times against the dated events of your life and sends the most likely window, with the evidence and a confidence level. First, the free range check shows how many rising signs fit.

Start my rectification — US$ 79

See a finished report first in the sample report.

How the houses are calculated

The chart is split into twelve houses. The first cusp is the ascendant and the tenth is the Midheaven; the others are placed by the Placidus method, the most common in Western astrology. Placidus cusps can't be calculated near the polar circles, so this tool covers places up to 66° of latitude.

Planets move slowly, but the cusps turn about a degree every four minutes. A planet close to a cusp can change house within half an hour, even when the rising sign stays the same. The list of planets that change house shows where a time that is a little off could matter.

Born in the US?

Birth records are kept by each state, so what appears on your certificate depends on the state and the year. Read how to find out what time you were born for where to look.

Short answers

Which house system does this calculator use?
Placidus, the most common house system in Western astrology.
Why would a planet change house if my time is a little off?
The house cusps move with the ascendant, about a degree every four minutes. A planet that sits near a cusp can end up on the other side of it within half an hour.
Does it handle daylight saving time?
The time you enter is read as the clock time at your place of birth in the US, using the historical time zone rules for that date, including daylight saving time. If the clocks went forward and your time falls in the skipped hour, the calculator tells you.

More free tools

Want more than a range? See what a full report looks like in the sample report, or start yours.

Astrology is a symbolic practice, not a science. Your report gives the most consistent birth-time window for the events you share. It is not a certified birth time.