Astrologer

Free Birth Chart Calculator

Enter a birth date, time, and place and get a full natal chart calculated with the Swiss Ephemeris — the same engine the professional desktop programs are checked against. No account, no email, and the chart is interactive rather than a static image.

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What you need to enter

Date, place, and time of birth. The time matters more than people expect: the Ascendant moves about one degree every four minutes, so it changes sign roughly every two hours. An approximate time gives you an approximate rising sign and approximate houses. Most countries record the time on the long-form birth certificate. Without one, the chart can still be cast — the Sun and outer planets stay correct, the Moon is usually right, and the Ascendant and houses are unknown rather than guessed at.

What the calculator gives you

An interactive chart wheel you can click placement by placement, a full aspect grid with orbs, essential dignity scoring, and the house and sign of every body. Beyond the traditional seven you can plot asteroids, fixed stars, midpoints, Arabic parts, and declinations with out-of-bounds planets flagged. Every placement carries an interpretation written for that specific combination rather than a generic sign description, and charts export as high-resolution PNG or PDF.

House systems and zodiacs

Twelve house systems are available — Placidus, Whole Sign, Equal, Vehlow, Koch, Porphyry, Regiomontanus, Campanus, Topocentric, Alcabitius, Meridian, and Morinus — plus both tropical and sidereal zodiacs with the Lahiri and Fagan-Bradley ayanamsas. These are set per chart, not globally, so you can compare a Whole Sign reading against a Placidus one without recasting.

How to check the chart is right

Cast the same chart on astro.com and compare the Ascendant and Midheaven, not the Sun — the Sun moves only a degree a day and looks correct even when the time conversion is broken. If the angles match, the timezone handling is sound. This is worth doing with any calculator, including this one: birth times are converted against the historical timezone database, so wartime daylight saving and half-hour zones resolve to the offset actually in force on that date.

What costs money and what does not

Casting charts, the 46 public calculators, and the glossary are free and need no account. Saving charts, client records, transit timelines against a saved chart, astrocartography, and AI readings require a subscription. Nothing about the calculation differs between free and paid — the ephemeris is the same.

Frequently asked questions

Is the birth chart calculator really free?

Yes. Casting a chart at astrologerapp.org requires no account, no email, and no payment. Saving charts, client records, and AI readings require a subscription.

Do I need my exact birth time?

For the Ascendant and houses, yes — the Ascendant moves about one degree every four minutes and changes sign roughly every two hours. Without a time the Sun and outer planets are still accurate and the Moon is usually right, but the rising sign and house placements cannot be determined.

What ephemeris does the calculator use?

The Swiss Ephemeris, accurate to about 0.001 arcseconds across the range 5400 BCE to 5400 CE. It is the same engine the established professional astrology programs are validated against.

Can I choose a different house system?

Yes. Twelve house systems are supported — Placidus, Whole Sign, Equal, Vehlow, Koch, Porphyry, Regiomontanus, Campanus, Topocentric, Alcabitius, Meridian, and Morinus — set per chart rather than globally.

Does it work on a phone?

Yes. The chart calculator runs in any modern browser on phone, tablet, or computer, with nothing to install.

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