Birth chart calculator

Enter your date, time and city of birth to draw your birth chart: the sign, degree and house of 10 planets, the Ascendant, the Midheaven and the major aspects, with whole sign or equal houses. Planet positions agree with the NASA JPL ephemeris to within 1 arcminute. The readings are traditional and for entertainment only.

Birth details

Please enter the local time at the place of birth, in 24-hour format.

Please type the name of the city and choose it from the list. If your place of birth is not listed, choose the nearest city.

House system

The details are saved only in this browser and are not uploaded.

Birth chart

Please complete the details. The result will appear here.

About this page

  • A birth chart, or natal chart, shows where the Sun, Moon and planets were on the zodiac at the moment and place of your birth.
  • The outer ring shows the twelve signs, the inner ring the twelve houses, and the lines in the centre the aspects between planets.
  • Your sun, moon and rising signs are often called your big three. They are the parts of a chart that people consult most often.
  • An error of 4 minutes in the birth time moves the Ascendant by about 1 degree, so an uncertain birth time makes the Ascendant and houses uncertain as well.

The readings on this page are traditional, for entertainment only, and not a basis for decisions.

Aspect

Two planets form an aspect when the difference in their longitudes is within the orb of one of these angles.

AspectAngleOrbNature
Conjunction0°±8°Depends on the planets
Sextile60°±6°Harmonious
Square90°±8°Tense
Trine120°±8°Harmonious
Opposition180°±8°Tense

The twelve houses

HouseTraditional area of life
1st housethe self and the impression you make
2nd housemoney and possessions
3rd housecommunication and learning
4th househome and family
5th housecreativity, leisure and romance
6th housedaily work and habits
7th housepartners and cooperation
8th houseshared resources and close bonds
9th housetravel, beliefs and further study
10th housecareer and public image
11th housefriends and groups
12th housesolitude and the inner life

How it is calculated

  1. Birth places come from the GeoNames city data. Coordinates are accurate to about 1 km, and each city has its IANA time zone.
  2. The birth time is converted to Universal Time using the UTC offset in force at the place on that date, including daylight saving time, as given by the time zone data in your browser.
  3. The positions of the Sun, Moon and planets are calculated with Astronomy Engine as apparent geocentric ecliptic longitudes, measured from the true equinox of the date.
  4. The Ascendant and Midheaven are calculated from the apparent sidereal time at Greenwich, the latitude and longitude of the birth place, and the true obliquity of the ecliptic.
  5. Whole sign houses: the whole sign containing the Ascendant is the 1st house, and each following sign is the next house. Equal houses: each house is 30 degrees, starting from the Ascendant.
  6. Aspects are measured from the difference in ecliptic longitude, with the orbs shown in the aspect table. If no birth time is given, the chart is set for 12:00 noon without the Ascendant or houses.
  7. The planetary positions at 5 moments were checked against the NASA JPL Horizons ephemeris. No planet differed by more than 17 arcseconds. For 3 published charts, the Ascendant and Midheaven differed from the results on this page by no more than 1 arcminute.
  8. All calculations are done in your browser. The birth details you enter are not sent to any server and are saved only in this browser.

Sources

  1. Astronomy Engine: Library for calculating the positions of the Sun, Moon and planets (MIT licence)
  2. NASA JPL: Horizons System (used to check the planetary positions on this page)
  3. GeoNames: cities15000 city data (CC BY 4.0)

Last reviewed on October 31, 2026.