Panchang for any date

Panchang means five limbs, and that is exactly what it is: tithi, vara, nakshatra, yoga and karana. Between them they describe the quality of a day in a way the Gregorian calendar cannot.

The tithi is the lunar day, measured as each twelve-degree step the Moon gains on the Sun. Because the Moon's speed varies, a tithi can run anywhere from about nineteen to twenty-six hours, which is why tithis do not line up neatly with calendar dates and why the same date can carry different tithis in different places.

The yoga here is the nityayoga, one of twenty-seven divisions of the combined longitude of the Sun and Moon, and should not be confused with the planetary yogas read in a birth chart. The karana is half a tithi, and the vara is the weekday.