How accurate is Kundali GPT?

The short version

The astronomy is accurate to a small fraction of a degree and can be checked against any professional ephemeris: for the same birth details and the same ayanamsa, the chart here agrees with Drik Panchang, AstroSage and Jagannatha Hora to within about a minute of arc. The astrology is a traditional practice rooted in belief, and no amount of computational precision changes that. Those are different claims and we try never to blur them.

Last reviewed 23 August 2026.

How the chart is calculated

• Planetary positions come from VSOP87 for the Sun and planets and ELP for the Moon, the same theories professional ephemerides are built on, via the astronomia library, with light-time and aberration corrections. Rahu and Ketu are the mean lunar node, the usual Vedic convention.
• The sidereal shift uses the Lahiri (Chitrapaksha) ayanamsa, adopted by the Indian government's calendar reform committee and the standard for Vedic work. The value used is printed on every chart and calculator result.
• Your birth moment is resolved through the IANA time zone that actually applied at that instant, not a fixed offset. India ran +5:53:20 until 1906 and only settled on +5:30 in 1955; for births before 1906 the form also offers local mean time.
• The ascendant is computed from apparent sidereal time at your birth coordinates, which is why a real city and a real birth time are both required.
• Houses are whole-sign, the Parashari default and what almost every Indian chart uses. The KP and Western chart calculators use Placidus cusps, as those systems do.

Where it can still be wrong

• Your birth time. The ascendant moves a degree every four minutes. A time recorded to the nearest half-hour, which is common, can put the ascendant in the wrong sign entirely. This is by far the largest source of error and it is not something the software can fix. The lagna calculator shows how many minutes of margin your recorded time has, and birth-time rectification narrows a rough window from dated events.
• Pre-1906 births in India. Records from that period were often kept in local mean time rather than any standard zone, which can shift the ascendant by several degrees. The form offers a local mean time option for these dates; choose it if that is how the time was noted, and the standard zone if not.
• Ayanamsa choice. We use Lahiri. Raman sits about 1.5° behind it and Krishnamurti (KP) a few minutes of arc ahead, so a planet or lagna near a sign boundary can land in the next sign on a site that uses a different one. Compare degrees, not only sign names.
• The nodes. We use the mean lunar node, standard in Vedic practice. The true node oscillates around it by up to about 1.7°, so a site using the true node can show Rahu and Ketu a degree or so away.

And the AI reading?

A different question. The AI astrologer only ever sees the computed chart, is instructed to answer from those placements alone and to cite them, and is told to say so when the chart does not support an answer. It will not predict a death, hands medical, legal, financial and psychiatric questions to a professional, and reports doshas with their classical cancellations. That makes the reading traceable; it does not make it true. The AI astrologer page sets out what it can and cannot do.

What we do not claim

• That astrology predicts anything. There is no scientific evidence for it, and we present the tradition as a tradition.
• That a reading here substitutes for medical, legal, financial or psychological advice. It does not, and the AI is instructed to hand those questions back.
• That we are connected to OpenAI. Kundali GPT is independent and not affiliated with or endorsed by OpenAI or ChatGPT. The chart is computed by our own code; a general language model, reached through an API gateway, only interprets it.

If you find a calculation you believe is wrong, please tell us: send the birth details, the figure you got and the source you are comparing against.