Calculation Method
All calculations happen in your browser and what you enter is not sent anywhere (only your chosen city and jaap count stay in your own browser). The rules, ayanamsa, house system and sources are written here; the rules were last checked on 10 October 2026, and the Panchang for four examples matched Drik Panchang to within two minutes.
Calculation Method
All calculations happen in your browser, and what you enter is not sent anywhere (only your chosen city and jaap count stay in your own browser). The rules were last checked on 10 October 2026.
Basis of calculation
- Planetary positions: calculated with the open-source astronomy library astronomy-engine 2.1.19 (MIT licence).
- Ayanamsa: Lahiri (Chitrapaksha).
- House system: whole-sign houses.
- Rahu-Ketu: mean node.
- Sunrise: upper limb of the Sun's disc, standard atmospheric refraction, observer at sea level.
- Local time to universal time: IANA time zone data, which includes the +06:30 period of 1941 to 1945.
- Birth place search: GeoNames data (CC BY 4.0).
Where your information stays
The calculation runs in your browser, and no birth details are sent to any server. The city you choose and your jaap count stay in your own browser. The details are at Privacy Policy.
How we checked
- We matched the Panchang for four examples (Delhi 10-10-2026, Mumbai 08-11-2026, Kolkata 15-03-2026, Surat 20-12-2026) against Drik Panchang: the end times of sunrise, sunset, tithi, nakshatra, yoga and karana, and Rahu Kaal agreed within 1 to 2 minutes. The limit for moonrise and moonset was set at 5 minutes.
- The Lahiri ayanamsa came out 0.0067 degrees away from the reference true value (on 10-10-2026), which equals less than a minute of the Moon's motion.
- Saturn's entry into Meena (29 March 2025) was checked against two published pages; Saturn's position is sampled once a day, so dates can differ by a day.
- For old time zone cases, the IANA data rules were checked.
What remains
- The lagna check so far rests on sunrise-time geometry; a comparison of charts with other software is still pending.
- In Guna matching, there are several regional forms of the Gana points; the form we use is stated on the tool's page.
- In Upapada Lagna, for the signs with two lords (Vrishchika, Kumbha), a single classical lord has been taken.
- On the Griha Pravesh rule, there is a small difference between the rule we chose and the classical text; its review is pending.
The sources are at Sources and References, and changes to the rules will be announced at Rule Updates.
The reference pages and texts our rules and tables were taken from or compared with, listed by topic, with the tools that use them and the date they were checked.
Rule UpdatesChanges to the rules and tables behind our tools, with the date they take effect and the tools affected, newest first.