Exactly how your kundli is calculated
Six steps, in the order they happen. Nothing is hidden, and you can check the arithmetic yourself using the worked example.
- 1
Birth place to coordinates and time zone
Your place of birth is resolved to latitude, longitude and the civil time zone that applied there on your date of birth.
- 2
Local time to Universal Time
Your birth time is converted to Universal Time and then to a Julian Day, the continuous time scale astronomers use for planetary calculation.
- 3
Planetary longitudes, then sidereal
Positions of the Sun, Moon, Mars, Mercury, Jupiter, Venus, Saturn and the lunar nodes are computed from a planetary ephemeris, then shifted to the sidereal zodiac by subtracting the Lahiri ayanamsa. A planet is marked retrograde when its apparent motion is westward. Rahu and Ketu are always exactly 180° apart.
- 4
Lagna and houses
The ascendant is found from local sidereal time and your latitude. Houses are whole-sign: the rising sign is the 1st house and each following sign is the next house.
- 5
Nakshatra and pada
The zodiac’s 360° is divided into 27 nakshatras of 13°20′, each split into four padas of 3°20′. Every planet is located within this grid.
- 6
Vimshottari dasha
The Moon’s nakshatra lord starts your sequence. The unexpired fraction of that nakshatra sets the balance of the first dasha, and the rest follow in the fixed order and lengths of the 120-year cycle, each split into antardashas in proportion.
Worked example: the sample Moon
- Moon: 27°47′49″ Sagittarius, and Sagittarius starts at 240°.
- Sidereal longitude: 267°47′49″
- Divide by 13°20′ to get 20.08, so the 21st nakshatra, Uttara Ashadha (ruler: Sun).
- Elapsed in the nakshatra: 1°07′49″, about 8.5%, so pada 1.
- Sun dasha balance: (1 − 0.085) × 6 years ≈ 5.49 years at birth.
Dasha order and years: Ketu 7, Venus 20, Sun 6, Moon 10, Mars 7, Rahu 18, Jupiter 16, Saturn 19, Mercury 17. Total 120.
Method at a glance
- Zodiac
- Sidereal
- Ayanamsa
- Lahiri (Chitrapaksha)
- Houses
- Whole sign
- Dasha system
- Vimshottari, 120 years
- Main chart
- D1 Lagna, North Indian
How birth time affects your chart
Not every part of a kundli is equally sensitive to the minute of birth. Here is what to expect if your time is approximate.
| Part of the chart | Why it moves | What a time error means | Sensitivity |
|---|---|---|---|
| Moon sign & nakshatra | The Moon moves about 13° a day, roughly 0.5° an hour. | Changes only if the time is hours off, or the Moon is near a sign boundary. | Low |
| Vimshottari dasha | Depends on the Moon’s exact degree within its nakshatra. | Dates can shift by weeks for a time error of an hour or more. | Medium |
| Lagna (Ascendant) | A sign rises about every 2 hours, roughly 1° every 4 minutes. | The most time-sensitive part of the chart. | High |
| Divisional charts | The Navamsa (D9) of the Lagna changes about every 13 minutes. | Needs an accurate birth time to be meaningful. | Very high |
Best sources for birth time: the birth certificate or hospital record, then a family diary or horoscope made at the time. Times are averages and vary with the sign and your latitude.