Birth Chart Calculator
Enter a birth date, local time, UTC offset, latitude and longitude to see where the Sun, Moon and planets sat in the tropical zodiac, plus the rising sign and whole-sign houses. It is an entertainment and learning tool, not a prediction.
Last updated November 4, 2026
1800 to 2050.
1 to 12.
Local clock time, 0 to 23.
Local time minus UTC, with daylight saving included: -5, 5.5, 1. Range -12 to 14.
North positive, south negative (-66 to 66).
East positive, west negative (-180 to 180). New York is -74.01.
Result
Sun 26°37' Taurus, Moon 26°29' Aquarius, Rising 2°57' Libra
| Body | Position and house |
|---|---|
| Sun | 26°37' Taurus, house 8 |
| Moon | 26°29' Aquarius, house 5 |
| Mercury | 7°56' Taurus, house 8 |
| Venus | 15°28' Aries, house 7 |
| Mars | 20°03' Pisces, house 6 |
| Jupiter | 10°01' Cancer, house 10 |
| Saturn | 25°08' Capricorn, house 4 (retrograde) |
| Uranus | 9°07' Capricorn, house 4 (retrograde) |
| Neptune | 14°18' Capricorn, house 4 (retrograde) |
| Ascendant | 2°57' Libra, house 1 |
| Midheaven | 3°25' Cancer |
| Elements | Fire 1, Earth 5, Air 1, Water 2 |
| Modalities | Cardinal 5, Fixed 3, Mutable 1 |
Show the work
Formula: Julian day, then Sun and Moon from Meeus, planets from JPL Keplerian elements, angles from local sidereal time
- Local time 1990-05-17 14:30 at UTC-5 becomes UT by subtracting the offset. Julian day JD = 2448029.31250.
- T = (JD - 2451545.0) / 36525 = -0.09625428 Julian centuries since J2000.
- Sun: mean longitude L0 = 55.2384 deg, mean anomaly M = 132.4665 deg, equation of centre C = 1.3929 deg. True longitude = 56.6313 deg; with aberration and nutation the apparent longitude is 56.6289 deg.
- Moon: mean longitude L' = 334.2241, elongation D = 278.9859, Sun anomaly M = 132.4665, Moon anomaly M' = 282.5311, argument of latitude F = 23.0108 deg. The periodic series adds -7.7382 deg, giving 326.4891 deg.
- Planets: each element is a0 + rate x T, the mean anomaly M = L - perihelion longitude is solved for the eccentric anomaly E (Kepler), the position is rotated into the ecliptic, Earth's position is subtracted, and precession plus nutation move it to the equinox of date. Jupiter, for example: M = 87.5811 deg, E = 90.3541 deg.
- Greenwich sidereal time = 167.7325 deg; add the longitude -74.01 deg (east positive) and the nutation term: local sidereal time = 93.7255 deg. Obliquity = 23.4422 deg.
- Midheaven = 93.4187 deg (3°25' Cancer); Ascendant at latitude 40.71 = 182.9571 deg (2°57' Libra).
- Whole-sign houses: house 1 is the whole of Libra, then each next sign is the next house. Each body takes the house of the sign it is in.
Result: Sun 26°37' Taurus, Moon 26°29' Aquarius, Ascendant 2°57' Libra
How the chart is calculated
UT = local time - UTC offset
T = (JD - 2451545) / 36525
Ascendant from local sidereal time, obliquity and latitude
Your local time becomes universal time using the offset you enter, then a Julian day and T, the centuries since 2000. The Sun follows Meeus, Astronomical Algorithms, chapter 25, and the Moon uses the 35 largest terms of chapter 47. Mercury to Neptune use NASA JPL Keplerian elements for 1800 to 2050.
The Ascendant is the zodiac degree rising on the eastern horizon; the Midheaven crosses the meridian overhead. Both follow from local sidereal time, and the Ascendant also depends on latitude.
Positions are tropical: 0 degrees Aries is the March equinox point. Sidereal charts, common in Vedic astrology, subtract about 24 degrees, so most planets fall one sign earlier. This page gives tropical output only.
See how we calculate for the formulas, sources and review schedule behind every calculator.
Whole-sign houses
In the whole-sign system the entire sign of the Ascendant is the first house, the next sign is the second house, and so on around the circle. Placidus and other unequal systems are not included.
Accuracy and limits
Against NASA JPL Horizons the Sun was within 0.01 degrees, the Moon and Mercury to Mars within about 0.02, Jupiter and Uranus within about 0.1, and Saturn within 0.17. A body close to a sign edge may land in the neighboring sign.
Years run from 1800 to 2050 because the planet formulas are fitted only for that span. Latitude is limited to 66 degrees north or south, since the Ascendant degrades near the polar circles.
Daylight saving is not guessed. Enter the offset in force at the birthplace, for example -4 for New York in summer. A one-hour error moves the Ascendant about 15 degrees.
Sources
Official and primary sources for the statements on this page. Their authors have not reviewed or endorsed this page.
- E.M. Standish and J.G. Williams, Keplerian Elements for Approximate Positions of the Major Planets, NASA JPL Solar System Dynamics, Table 1 (1800-2050). Planet positions (Mercury to Neptune), fetched 4 November 2026.
- Jean Meeus, Astronomical Algorithms, 2nd ed., Willmann-Bell, 1998, chapters 7, 12, 14, 22, 25 and 47. Julian day, sidereal time, Ascendant and Midheaven, Sun and Moon.
- NASA JPL Horizons system API. Independent reference longitudes used to test this calculator.
How to use the Birth Chart Calculator
- Enter the birth year, month, day, hour and minute as shown on a local clock.
- Enter the UTC offset in hours, such as -5 or 5.5, including daylight saving if it applied.
- Enter latitude (north positive) and longitude (east positive) of the birthplace.
- Read the table of signs, degrees and houses, and open Show the work for the steps.
Example: 17 May 1990, 14:30, New York
Local time 14:30 at UTC-5, latitude 40.71, longitude -74.01. Julian day 2448029.3125.
| Body | Position | House |
|---|---|---|
| Sun | 26°37' Taurus | 8 |
| Moon | 26°29' Aquarius | 5 |
| Mercury | 7°56' Taurus | 8 |
| Venus | 15°28' Aries | 7 |
| Mars | 20°03' Pisces | 6 |
| Jupiter | 10°01' Cancer | 10 |
| Saturn (retrograde) | 25°08' Capricorn | 4 |
| Ascendant | 2°57' Libra | 1 |
| Midheaven | 3°25' Cancer | - |
Frequently asked questions
Why does the exact birth time and place matter?
The Moon moves about half a degree per hour and the Ascendant about one degree every four minutes, so both set the rising sign and houses.
What is the difference between tropical and sidereal?
Tropical signs start at the March equinox, while sidereal signs are shifted by about 24 degrees to match the stars. This calculator is tropical only.
Why is my latitude limited to 66 degrees?
Near the polar circles some zodiac degrees never rise, so the Ascendant becomes unreliable and results would mislead.
Does this predict anything about my life?
No. It reports astronomical positions and sign names for entertainment and learning, and nothing here forecasts events, character or health.