Thirty degrees from the ascendant
Equal houses start at the exact degree of your ascendant and run in thirty-degree steps from there. If your ascendant is at seventeen degrees of Libra, your second house begins at seventeen degrees of Scorpio, the third at seventeen degrees of Sagittarius, and so on.
It keeps the ascendant precise, which whole sign gives up, and it keeps the houses even, which quadrant systems give up. That combination is the case for it.
What it does with the Midheaven
It ignores it. The tenth cusp in an equal house chart is simply ninety degrees before the ascendant, and the actual Midheaven falls wherever geometry puts it, often several degrees away.
Supporters treat that as honest: the Midheaven is a real point and forcing it to be a house cusp distorts the division. Critics treat it as discarding the second most important angle in a chart.
This calculator shows where your Midheaven actually falls alongside the equal cusps, so you can see the gap rather than having it hidden.
Where it sits between the alternatives
| System | Ascendant | House sizes | Midheaven |
|---|---|---|---|
| Placidus | Exact, on the cusp | Uneven | Tenth cusp by definition |
| Equal | Exact, on the cusp | All thirty degrees | Floats |
| Whole sign | Somewhere in house one | All thirty degrees | Floats |
Equal is the middle option: more precise than whole sign about the ascendant, more stable than Placidus about house sizes.
Where it holds up best
At high latitudes. Because it needs only the ascendant, it has a solution everywhere on Earth, unlike Placidus. Charts cast for northern Scandinavia or Alaska work normally.
It also produces no interceptions, since every house is exactly one sign wide, though the signs are offset rather than aligned as they are in whole sign.
The variant that starts at the Midheaven
A related method builds equal houses from the Midheaven instead, making it the tenth cusp and letting the ascendant float. It is sometimes called the M-house or equal-from-MC system.
It is a minority practice and is not offered here. Knowing it exists is useful mainly because it explains occasional disagreements between tools that both call themselves equal house.
A note on history
Equal houses appear in Hellenistic sources alongside whole sign and were used in the Islamic tradition, so the system is old. Its modern revival in the twentieth century came largely through British astrologers, and it remains more common in Britain than in North America.
That regional split is worth knowing when comparing a reading with someone else's: two competent astrologers can produce different house placements for the same chart without either being careless.
Why it needs a birth time
The whole system hangs off the ascendant degree, which moves about one degree every four minutes. An hour of error moves every cusp fifteen degrees, and any body near a boundary changes house.
Unlike whole sign, equal houses do not tolerate an approximate time. If yours is uncertain, whole sign gives you a more stable chart and the comparison table shows what the difference costs.
Common questions
How do equal houses work?
Thirty-degree houses running from the exact degree of your ascendant. An ascendant at seventeen degrees Libra puts the second cusp at seventeen degrees Scorpio.
What happens to the Midheaven?
It floats, often several degrees from the tenth cusp. This calculator shows where it actually falls rather than hiding the gap.
How is this different from whole sign?
Whole sign starts each house at zero degrees of a sign; equal starts each at your ascendant degree. Equal keeps the ascendant precise, whole sign keeps the houses aligned with the signs.
Does it work at high latitudes?
Yes. It needs only the ascendant, so it has a solution everywhere on Earth, unlike Placidus.
Are there interceptions?
No, since every house is exactly thirty degrees. The signs are offset from the houses rather than aligned with them.
How precise does my birth time need to be?
Precise. Every cusp hangs off the ascendant degree, so an hour of error moves them all fifteen degrees. Whole sign tolerates an approximate time far better.