Calculate your rising sign

Your rising sign, or Ascendant, is the zodiac sign that was climbing the eastern horizon at the exact minute and place you were born. It moves through all twelve signs roughly every twenty-four hours, so it changes about every two hours, and is the single placement most sensitive to birth time.

The Ascendant is computed from Astronomy Engine using your exact birth moment and birthplace coordinates, to within about one arcminute of precision. Because it moves so quickly across the sky, the result is only as accurate as the birth time and birthplace you provide.

Without a clock time there is no single rising sign, but for your birth date and birthplace there is a short, exact list: tick I don’t know the birth time and this page shows the sign that was rising in each two-hour window of that day, with the minute of every change, so you can find the window you were born in. The rising sign changes about every two hours on average, but not evenly: at London's latitude one sign can rise in under an hour and another take almost three. The Estimate with sunrise option adds an approximate Ascendant for local sunrise, clearly marked as an estimate.

Because the Ascendant changes roughly every two hours, a birth time within a few minutes of one of those changeovers can land right on the edge between two signs. A small error in the recorded birth time or the historical time zone is enough to move the result to the neighbouring sign, more so than for any other placement in the chart.

This calculator uses the tropical zodiac, where the Ascendant's position is measured from the seasonal starting point at zero degrees Aries rather than from a fixed star. Most Western rising-sign readings, including this one, use this convention.

The Ascendant is the intersection of the ecliptic with the local horizon, so it depends directly on the latitude and longitude you were born at, not only on the time. The birthplace also supplies the historical time zone needed to convert your entered local time into the correct astronomical instant before that horizon is calculated. For a birth before 1970 in a small set of zones — mostly the Low Countries, Scandinavia and the former Yugoslavia — the historical rules come from the tzdata backzone (release 2025c), compiled into the site.

No. The calculation runs entirely in your browser using a local astronomy library and an offline city list; birth details are not sent for calculation or placed in the URL. This browser remembers them on this device for next time unless you choose Don’t remember, and Forget removes them. If you choose Keep this chart, its birth details are saved to your optional account until you delete them.