Birth-time accuracy for Kundli matching: unknown and uncertain times
Why recorded birth time, historical timezone and birthplace matter, and what Astrogyana withholds when time is unknown.
An explanation of Astrogyana’s implemented methodology. Updated:
हिंदी में पढ़ेंUse a record, and preserve its uncertainty
Use the best available birth record and enter the local clock time it gives. If the record is rounded or recalled approximately, keep that uncertainty in mind when reading the chart. Entering an invented minute makes the input look precise without making it more reliable.
The ascendant depends on time and location. D9 divisions can also change around boundaries. The Moon may cross a sign or nakshatra boundary during a day, affecting matching factors and the initial Vimshottari period. There is no universal number of minutes that is safe for every chart.
Historical timezone handling matters
The site uses the birthplace's IANA timezone and historical offsets. During a daylight-saving clock change, some local times do not exist; others occur twice. Nonexistent times are rejected. Repeated times need an explicit UTC offset so the instant is unambiguous.
Confirm the selected place rather than substituting your current city. The form also allows coordinates and timezone to be inspected. A mismatch should be corrected before saving or buying a report, rather than treated as an interpretive disagreement.
What happens when you do not know the time
The individual Kundli tool offers an unknown-time mode. It uses local noon for explicitly approximate planetary positions and withholds ascendant, houses, D9 and dashas. Noon is not a recovered birth time. The result warns that a Moon sign or nakshatra can change within that day.
The matching tool and detailed paid reports require recorded times. The application does not perform birth-time rectification. If you cannot supply a time, use the limited individual chart and avoid presenting it as an exact matching result.
Worked example: what changed across ten minutes
This is an actual, non-saved calculation for two fictional people. It contains no customer data and is not a relationship outcome study. Both charts use True Chitra, whole-sign houses and the true node.
Example updated: · north-india-basic-2026.2 · de440s-natal-2026.4
Three instants for the same New Delhi profile
Keep A's date of 1 January 1990 and coordinates 28.6139, 77.209 fixed, then compare 09:20, 09:30 and 09:40 IST. These rows come from a ±10-minute window sampled every minute.
| Local time | D1 ascendant | D9 ascendant | Moon star/pada |
|---|---|---|---|
| 09:20 IST | Capricorn | Gemini | Dhanishta · 4 |
| 09:30 IST | Capricorn | Cancer | Dhanishta · 4 |
| 09:40 IST | Capricorn | Leo | Dhanishta · 4 |
D1 stays in Capricorn and the Moon star/pada stays the same in these samples, while the D9 ascendant changes from Gemini to Cancer to Leo. Some classifications remain stable while others change. This is a sensitivity check, not a method of determining the true birth time.
Sources and scope of this example
- Skyfield — astronomical time scales
Explains civil and astronomical time. It is not the source of the traditional matching tables.
- Swiss Ephemeris — sidereal references and independent comparison
Documents sidereal conventions and comparison settings. Astrogyana calculates with Skyfield/JPL; Swiss is used for independent reference tests.
Compare using your own birth details
The free tool requires both recorded birth times. Read the explanations and choose a paid option only if it is useful to you.
Try free Kundli matchingSources and corrections
This guide documents north-india-basic-2026.2 and de440s-natal-2026.4. The raw score and selected exceptions are separate. Other traditions can use different rules.