Astrology calculator
Build a chart for any moment between 1900 and 2200, see where the planets stood, and read the aspects off the wheel. Swiss Ephemeris underneath, nothing to install.
Birth chart
Planets, houses, aspects and the wheel, from a date, a time and a place.
OpenTransits to a chart
What today's sky is doing to your own chart rather than to everyone's.
OpenSynastry
Two charts on one wheel, with the aspects between them.
OpenEphemerides
Where the planets stood on any day, month by month.
OpenThe sky today
Every planet's sign and degree right now, and the Moon's phase.
OpenWhat a calculator does, and what it does not
A chart is a snapshot of the sky from one point on Earth at one instant. Give a calculator a date, a time and a place and it works out where every planet stood, which sign each fell in, how the houses were divided and which planets were talking to each other. That is arithmetic, and a good engine gets it right to the arc minute.
What arithmetic will not tell you is what any of it means for a life. A chart showing Saturn on the Midheaven is a fact; whether that reads as a career built slowly and held for decades, or as a father whose approval still runs the show, depends on the rest of the chart and on the person living it. That is the part a reading does.
What this one computes
- · ten planets plus Chiron, the lunar nodes and Lilith, with degrees and retrogrades
- · twelve house cusps and their rulers, on the Placidus system
- · the aspects between the planets, with their orbs
- · essential dignities, so you can see which planets are working from strength
- · the wheel itself, which you can open full screen and zoom
A note on the birth time
The planets move slowly enough that a few hours either way rarely changes a sign. The houses do not: the whole wheel turns once a day, so a degree of the Ascendant is worth about four minutes of the clock. An hour of uncertainty moves the Ascendant by fifteen degrees, which is half a sign.
That is why this calculator refuses to show houses when you leave the time blank, rather than showing them with a caveat. If the time is genuinely lost, it can be recovered from dated events in a life — rectification is the technique for it.
Questions
Is this really free?+
Yes, and there is no account to make. The calculators are the open part of the site: they compute and show, and nothing is held back behind a form. What we sell is the written reading, which is a different thing entirely.
How accurate is the calculation?+
It runs on Swiss Ephemeris, the same engine professional astrology software uses, through our own service. Positions are computed for the exact moment and coordinates you give, with no rounding to noon or to a city centre unless you ask for it.
Can I build a chart for a date in the future?+
Any date from 1900 to 2200. The engine is equally happy with a birth in 1943 and with a wedding date in 2031, which is what makes it useful for electional work as well as for natal charts.
What if I do not know the birth time?+
Leave it empty and the chart is built for noon. The houses, the Ascendant and the Midheaven are then left out of the tables rather than shown with a warning: at noon those are invention, and a precise-looking degree gets believed whatever the caption says.
How is this different from professional astrology software?+
Desktop programs are built for daily professional work: dozens of techniques, directions, custom orbs, batch processing. This is the everyday half of that, in a browser, with nothing to install and nothing to configure. If you already own such a program you know why you own it.
Do you store what I enter?+
The calculation itself is cached, because a chart for a fixed moment at a fixed point never changes and recomputing it wastes everyone's time. What is stored is the moment and the coordinate, with no name, no email and nothing that identifies you.