Lahiri, KP or Raman? Why your kundli looks different in every app

Put the same birth details into two kundli apps and you can get two different charts: a different lagna, a different nakshatra pada, a different navamsa. Neither app has to be wrong. Most of the time the difference comes from one of three settings, and once you know them you can check which one is behind it.

I made a free calculator, astro.tukka.dev, that lets you change each of these settings and see the chart change.

The ayanamsa

Vedic astrology measures the planets against the stars, while the Western zodiac follows the seasons. The gap between the two is the ayanamsa, about 24° today and growing by roughly 50 arcseconds a year. Every Vedic chart subtracts it from the planets' positions, and astrologers don't agree on its exact size.

Lahiri (Chitrapaksha) is the Indian government's official ayanamsa and the default in most software. The others differ from it by fixed amounts:

1. Krishnamurti (KP) is about 6 arcminutes smaller than Lahiri.
2. B.V. Raman's is about 1°27′ smaller.
3. Fagan/Bradley, used in Western sidereal astrology, is about 53′ larger.

Those gaps sound small, but they move every planet and the lagna by the same amount. Switching from Lahiri to Raman changes the Moon's nakshatra for roughly one person in nine, its pada for about four in ten, and the navamsa sign of any planet just as often, because a navamsa is only 3°20′ wide.

If two apps disagree by about a degree and a half everywhere, check whether one of them uses Raman. If they disagree by a few arcminutes, look for KP.

The time zone at birth

A chart needs the exact moment of birth in universal time, which means knowing the clock offset in force that day, not today's. For most of the Second World War, from late 1941 to October 1945, clocks in India ran an hour ahead on war time (UTC+6:30), so a calculator that assumes UTC+5:30 for those births puts the lagna roughly 15° off. Births abroad have the same problem with daylight saving. The United States, for example, ran daylight saving through January and February 1974.

Astro works the offset out from the place and date, using the time zone history built into your browser, and shows it under the place box. If your family records used a local time instead, you can type the offset yourself.

Rahu and Ketu: mean or true

The Moon's nodes can be calculated two ways. The mean node moves backwards at a steady rate. The true node wobbles around it by up to about a degree and a half. Some software uses one by default and some the other, so Rahu and Ketu can sit in a different nakshatra pada, or even a different sign near a boundary.

Seeing it for yourself

On Astro's kundli page, enter your birth details once and open Settings. You can switch between 13 ayanamsas (Lahiri, Raman, KP, Fagan/Bradley, Yukteshwar, True Chitra and others) or enter your own value, choose the mean or true node, and pick North or South Indian charts. The Rashi, Navamsa and Dashamsa charts redraw instantly, along with the nakshatra table and the Vimshottari dasha down to pratyantardasha.

Everything is calculated in your browser, so your birth details aren't sent anywhere, and each chart downloads as an image. The positions are checked against NASA's JPL ephemeris for every date from 1900 to 2100; the about page explains how, and lists what each ayanamsa is based on.