How we calculate your chart

1. The astronomical layer

Planetary positions come from the Swiss Ephemeris, via its built-in Moshier analytical model — the same engine used by professional astrological software. Our configuration is set once, at process start, and applies to every chart:

• Ayanamsa: Lahiri (Chitrapaksha) — the Government of India standard, and the assumption behind the classical material our rules are drawn from.
• House system: whole-sign — each sign is one house, counted from the Lagna. Every rule in our knowledge base was written against this convention. We don't offer Placidus or Sripati, because our rules would silently mean something different under them.
• Rahu and Ketu: true node, not mean node. The mean node can sit up to roughly 1.5° from the true position — enough, near a boundary, to place Rahu in the wrong nakshatra and start your entire Vimshottari dasha sequence on the wrong lord.
• Birth time is resolved in your actual timezone, including historical daylight-saving transitions.

From those positions we compute deterministically: sign, degree, nakshatra and pada for all nine grahas, retrograde state, the Lagna, dignity and combustion, Ashtakavarga, Shadbala, birth panchang, the Navamsha (D9) and Dashamsha (D10), and your current Mahadasha, Antardasha and Pratyantardasha. You can see the first of these for yourself on our free kundli tool, and the day's equivalent on today's panchang.

2. The deterministic layer — the rule engine

None of the above involves AI. Neither does the next step.

We maintain a knowledge base of classical rules stored as machine-readable schemas — not prose for a model to interpret, but conditions a program evaluates. 58 yogas and doshas are encoded as executable rules (42 yogas, 16 doshas), plus 6 transit-level yogas. A rule engine walks every one against your chart facts and returns exactly the set that fires, with strength modifiers and classical cancellations applied.

This inverts the usual order. The yogas in your reading are not the ones a language model recalled or thought sounded plausible — they are the ones a deterministic evaluation of your chart actually produced. Run the same birth data twice and you get the same set, every time. You can read how individual combinations work in our Raj Yoga and dasha explainers.

57 of those 58 rules carry a citation to the classical source they derive from — most often Brihat Parashara Hora Shastra, Phaladeepika, Brihat Samhita, and for horary questions, Prashna Marga.

3. The AI layer — and its limits

Only now does a model get involved. Four specialist agents (astrology, numerology, horary/Prashna, transits) each receive the computed chart facts and a filtered slice of the knowledge base. A supervisor agent synthesises their output into one reading; where two specialists disagree, the reconciliation weighting is fixed in code, not decided by the model.

The models' job is interpretation and language. What they are explicitly instructed not to do, in the prompt itself: contradict the computed chart facts; invent yogas, doshas, dignities or dasha lords beyond those supplied; or cite any classical entry not present in the reference slice they were given. On horary questions the yes/no verdict comes from the rule engine, and the model is forbidden from reversing it — its role there is phrasing and remedial guidance only.

4. The validation layer

Instruction alone isn't enough, so model output is checked before you see it.

Claims are validated against the chart facts computed in step 1. A named yoga that doesn't exist in our knowledge base is flagged as fabricated. A yoga that exists but did not fire for your chart is flagged too. Dasha lords are checked against your computed dasha; sign and dignity against the computed position; numerology values against the deterministic calculation; timing windows against plausibility. The default response to a failed check is removal — the claim does not reach you.

We'd rather state this precisely than impressively: coverage differs by specialist. The numerology agent runs a structured claim contract with field-level checking. The astrology agent runs a prose-level check that catches fabricated yoga and dignity statements. The horary verdict is deterministic by construction. The transit agent is not yet claim-validated. That is the honest current state, and the part we're still extending.

What we don't claim

We do not publish an accuracy percentage. You'll see competitors advertise figures like "90% accurate" — there is no methodology under which such a number could be honestly derived for astrological prediction, and quoting one would contradict everything above.

What we stand behind is narrower and real: the astronomy is computed to a published standard, the classical rules are evaluated deterministically and cite their sources, and model output is checked against those calculations before it reaches you. Astrology remains interpretive. Our calculations are not, and that is the part we hold ourselves to.