Private astrology calculator

Calculate your birth chart

A birth chart maps where the Sun, Moon and planets stood against the zodiac at the moment you were born; enter your birth city and time and it is calculated here, in your browser.

Your birth details

Enter the astronomical moment

Pick the birthplace — the zone follows.

Birth place

An offline city list. Nothing goes online.

Set the place manually

Coordinates are optional here. A recognized IANA time zone (for example Europe/Warsaw) is enough to apply the correct historical offset, but the rising sign and houses need latitude and longitude too.

Birth date
Birth time

Pick a city to apply its time zone

The birth moment and coordinates stay in this tab.

Ready when you are.

The Moon at Your BirthIts sign and exact degree — the tide beneath the day.Find your Moon →carries date · time · cityThe Eastern HorizonYour Ascendant — the sign climbing the sky as you arrived.Find your rising →carries date · time · citySun, Moon & RisingThe three anchors of a chart, read together on one page.Read the three →carries date · time · city

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Birth chart calculatorCalculate Sun, Moon, rising sign and planetary placements from one private form.Calculate a chart →Moon sign calculatorFind the Moon sign and exact zodiac degree for a birth moment.Find your Moon →Rising sign calculatorFind the Ascendant from an exact time and birthplace city.Find your rising sign →Big Three calculatorSun, Moon and rising sign in one private result.Find your Big Three →Synastry chart calculatorCompare two birth charts — every cross-aspect, house overlay and reading between them.Compare two charts →Composite chart calculatorBlend two birth charts into one — a midpoint composite or a real Davison chart for the pairing.Cast the composite →Transit chart calculatorSee which planets are contacting your birth chart today, and step through nearby dates.See today's transits →Solar return chart calculatorCast your solar or lunar return for any year — return-to-natal aspects and house placements.Cast your return →Planetary hours calculatorSee which planet rules this hour, day or night, for any city, and every hour around it.See today's hours →

Direct answer

What you need

Nothing is uploaded or placed in the URL. A cast is kept only in this tab's own memory — long enough for "Read next" — until you close the tab.

Method & limits

Astronomy first, symbolism second.

Calculations use the tropical zodiac and geocentric apparent ecliptic positions. A rising sign cannot be calculated responsibly without an exact time and place; near a sign boundary, a small input error can change the result.

Frequently asked questions

How accurate is this birth chart calculator?

Positions come from Astronomy Engine, an open-source ephemeris used across the site, computed to within about one arcminute of precision for the planets shown. The main source of error is your input: an uncertain birth time or an approximate birth city moves the Ascendant and house cusps far more than the engine itself does.

What if I do not know my exact birth time?

Leaving the birth time unknown still shows the Sun and planet signs for that date, computed from a neutral midday placeholder; the Sun's sign is effectively fixed for the whole day, though the Moon's can occasionally change partway through it. The Ascendant and house cusps need a real clock time, so they are left out rather than guessed, and this page's Estimate with sunrise option can fill in an approximate Ascendant for that date and birthplace instead.

What is a cusp birthday, and does it affect my chart?

A cusp birthday is one that falls within roughly a day of a sign changing, when the Sun's exact sign for your birth date depends on the hour and time zone rather than the calendar date alone. This calculator reads the real position for your exact birth moment, so a cusp birthday is resolved correctly as long as the date, time and time zone you enter are correct.

Does this use the tropical or sidereal zodiac?

This calculator uses the tropical zodiac, which measures sign boundaries from the seasons, where the point the Sun reaches at the spring equinox marks zero degrees Aries. It is the zodiac used by most Western astrology, as opposed to the sidereal zodiac, which is anchored to the visible constellations and runs roughly 24 degrees behind it today.

Why does the birthplace matter, not just the date and time?

The birthplace sets two things: the historical time zone, which converts your local birth time to the correct astronomical instant, and the horizon at that location, which the Ascendant and house cusps are measured against. The same birth moment produces a different chart in a different city, because the eastern horizon points somewhere else in the sky. 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.

Is my birth information sent anywhere?

No. The calculation runs entirely in your browser using a local astronomy library and an offline city list; nothing about your birth date, time or place is uploaded, stored on a server, or placed in the page URL.