How it works

Calculation Methodology

Astrology deserves the same rigor as astronomy — because the calculations underneath it are astronomy. Here is exactly how your chart is computed, with nothing hidden.

01

Swiss Ephemeris precision

Every planetary position on kundli.site is computed with the Swiss Ephemeris — the astronomical engine built by Astrodienst on NASA JPL ephemeris data. It is the same library professional astrology software uses, accurate to a small fraction of an arcsecond.

That precision matters more in Vedic astrology than anywhere else. A planet sitting 0.2° from a sign boundary can change its sign, its house, its nakshatra pada — and with it, the entire reading. We compute positions for your exact birth moment, corrected for your birthplace's longitude and the exact daylight-saving rules in force on your birth date.

  • Planetary longitudes from JPL-based ephemeris tables, not approximations
  • Birth-time correction for your exact longitude and historical timezone rules
  • Positions validated against independent implementations to within 0.005°
02

The sidereal zodiac and the Lahiri ayanamsa

Western astrology uses the tropical zodiac, anchored to the seasons. Vedic astrology uses the sidereal zodiac, anchored to the actual constellations. Because the Earth's axis slowly precesses, the two zodiacs have drifted apart by about 24 degrees over the millennia.

That drift is corrected by the ayanamsa — literally, “the measure of the equinox's movement.” We use the Lahiri ayanamsa, the official standard of the Government of India, as our default. Raman, Krishnamurti, and Fagan-Bradley ayanamsas are also supported, because honest astrology admits that traditions differ on the exact value.

  • Lahiri ayanamsa by default — the Indian government's official standard
  • Raman, Krishnamurti, and Fagan-Bradley available as alternatives
  • The ~24° tropical–sidereal difference applied transparently, never hidden
03

Whole-sign houses

Houses divide the sky into twelve fields of life — self, wealth, family, and so on. Vedic tradition reads houses whole-sign: the entire sign containing the ascendant is the first house, the next sign is the second, and so on.

This is not a simplification; it is the classical system of Parashara's tradition, and it is what the major Indian almanacs and chart services use. Your bhava chart follows the same convention, so a kundli.site chart reads the way a traditional astrologer expects it to read.

  • Whole-sign houses — the Vedic standard used by classical texts
  • Ascendant computed from your exact birth time and place
  • Comparable house-by-house with the major Indian chart services
04

The 27 nakshatras

The Moon's path is divided into 27 lunar mansions — the nakshatras — each spanning exactly 13°20′ of the zodiac, and each divided into four padas (quarters). Your birth nakshatra and its pada are the most personal coordinates in Vedic astrology: they name the Moon's exact station at your birth.

Every planet's nakshatra, pada, and nakshatra lord is computed and shown in your report. The nakshatra lord of your birth Moon decides something even more important — the starting point of your dasha sequence.

  • All 27 nakshatras mapped to the exact degree, with pada boundaries
  • Nakshatra lords assigned per the Vimshottari sequence
  • Birth nakshatra and pada shown for the Moon and every planet
05

The Vimshottari dasha clock

Vedic astrology's signature timing system is the Vimshottari dasha: a 120-year cycle of planetary periods — mahadashas — each subdivided into antardashas and finer periods. The sequence begins from the nakshatra lord of your birth Moon, and the remaining balance of the first period is prorated from the Moon's exact position within its nakshatra.

We compute the full sequence from your birth moment: every mahadasha with its start and end dates, every antardasha within it, and — highlighted on your report — the exact period you are living through right now. The current mahadasha, antardasha, and their remaining durations are always visible, because timing is the question most people actually come with.

  • Full 120-year Vimshottari sequence from your birth moment
  • First-period balance prorated from the Moon's exact nakshatra position
  • Current mahadasha and antardasha highlighted with remaining time

What calculations can't do

Perfect mathematics does not make a perfect prediction. The sky at your birth is a fact; what it means is an interpretation — and interpretations are for reflection, not certainty. We publish this methodology so you can judge the instrument. The meaning, as always, is yours to make.

Last updated: October 2026