Panchang Guide — Tithi, Nakshatra, Yoga, Karana Explained

Panchang: A Complete Guide

A panchang answers a question people have asked for millennia: what kind of day is this? Not in a vague sense, but measurably — where the Sun and Moon actually stand, how far apart they are, and what that means for the work you are about to begin. This guide explains each element, how the figures on this site are produced, and how much confidence to place in them.

On this page

What is Panchang?
What is Tithi?
What is Nakshatra?
What are Yoga and Karana?
How is the calculation performed?
How should you interpret the results?
Why does Panchang change for different locations?
What astronomical data does the tool use?
How accurate are the calculations?

1. What is Panchang?

The word is a compound of two Sanskrit terms: pancha, meaning five, and anga, meaning limb. A panchang is the almanac built from five limbs — tithi, nakshatra, yoga, karana and vara — each a distinct astronomical measurement of the same moment.

The important thing to grasp is that a panchang is not a calendar. A calendar assigns names to days by counting; a panchang measures the sky. Every entry is derived from the true positions of the Sun and Moon for a specific place and instant, which is why two panchangs for the same date can legitimately differ if they were computed for different cities.

Traditionally the panchang served as the practical interface between astronomy and daily life. It told a farmer when to sow, a family when to marry, a merchant when to open a ledger. That function survives: the five limbs are still consulted for choosing auspicious times, observing fasts and festivals, and understanding the character of a day.

In the Vedic reckoning the day begins at sunrise, not at midnight. A panchang entry therefore describes the period from one sunrise to the next, and the elements it names are those in force at sunrise. Because tithi and nakshatra change at their own pace, a single civil day frequently contains a transition from one to the next, and a full panchang gives the time at which that change occurs.

2. What is Tithi?

A tithi is the lunar day: the time the Moon takes to gain 12 degrees of longitude on the Sun. Since a full cycle is 360 degrees, thirty tithis complete one lunar month.

The month divides into two fortnights of fifteen tithis each. Shukla paksha is the waxing half, running from the new moon to the full moon as the Moon pulls ahead of the Sun. Krishna paksha is the waning half, from full moon back to new.

The subtlety that surprises people is that a tithi is not a fixed length. The Moon's orbit is elliptical, so its angular speed varies — faster near perigee, slower near apogee. A tithi therefore runs anywhere from roughly 19 to 26 hours.

Two consequences follow, and both are normal rather than errors:

A tithi rarely aligns with a civil day. It can begin at any hour and end at any hour.
Occasionally a tithi is skipped (kshaya) because it begins and ends entirely between two sunrises, or repeated (adhika) because it spans two sunrises.

The tithi in force at sunrise is the one conventionally assigned to the day. Several tithis carry particular observances — Ekadashi, the eleventh, is widely kept as a fast day; Purnima and Amavasya, the full and new moons, mark the fortnight boundaries.

3. What is Nakshatra?

The nakshatras divide the ecliptic into 27 segments of 13°20' each, often called lunar mansions. The nakshatra of a panchang entry is the one the Moon occupies.

Of all five limbs, nakshatra carries the most weight in practice. When a muhurta is chosen, the nakshatra is usually consulted first: each has a ruling planet, a symbol, a presiding deity and an established character. Some suit beginnings and travel, others rest, repair, dissolution or completion.

Each nakshatra subdivides into four padas of 3°20', and the pada matters for finer work — it determines the navamsa position of a planet, and therefore feeds directly into the divisional charts used for marriage and career.

The nakshatra also anchors the timing system of Vedic astrology. The Vimshottari dasha cycle assigns each of nine planets a fixed number of years across a 120-year span, and the period running at your birth is set by the nakshatra your Moon occupied — which is why the Moon's exact degree at birth matters so much.

The Moon travels roughly 13 degrees a day, so it crosses a nakshatra in a little under 24 hours. A given day usually sees one nakshatra transition.

4. What are Yoga and Karana?

Yoga is calculated from the sum of the solar and lunar longitudes, divided into 27 parts of 13°20'. Note the difference from tithi, which uses the difference between the two.

This is a persistent source of confusion: the 27 yogas of the panchang have nothing to do with the planetary yogas of a birth chart, such as Gaja Kesari or the Pancha Mahapurusha combinations. They share a word and nothing else.

Several yogas carry strong traditional associations. Siddha, Amrita and Shubha are regarded as favourable. Vyatipata and Vaidhriti are the two most consistently avoided for beginning anything of consequence, and a full panchang will mark them.

Karana is the half-tithi: the Moon gaining 6 degrees on the Sun. Two karanas fill each tithi, giving sixty in a lunar month, drawn from a set of eleven names.

The eleven split into two groups. Four are fixed (sthira) — Shakuni, Chatushpada, Naga and Kimstughna — and occur once per lunar month at set points around the new moon. The remaining seven are movable (chara) and rotate continuously through the rest of the month, each appearing eight times.

Karana is consulted mainly for short, practical undertakings rather than major life events. The one most often noted is Vishti, commonly called Bhadra, which is traditionally avoided for auspicious work.

5. How is the calculation performed?

Every element derives from two numbers: the ecliptic longitude of the Sun and the ecliptic longitude of the Moon, at the moment in question, expressed in the sidereal zodiac.

The sequence is:

Convert local time to Universal Time, then to a Julian Day — the continuous day count astronomical algorithms operate on.
Compute the tropical longitudes of the Sun and Moon for that instant.
Subtract the ayanamsa to obtain sidereal longitudes. This site uses Lahiri (Chitrapaksha), the standard adopted by the Indian calendar reform committee and used by most published panchangs. The ayanamsa is computed for the date rather than taken as a fixed figure, because it drifts by about 50 arcseconds a year.
Derive each limb from those two longitudes:

Element	Formula
Tithi	(Moon − Sun) ÷ 12°, giving 1–30
Nakshatra	Moon ÷ 13°20', giving 1–27
Yoga	(Moon + Sun) ÷ 13°20', giving 1–27
Karana	(Moon − Sun) ÷ 6°, giving 1–60
Vara	The weekday, changing at local sunrise

Compute sunrise and sunset for the coordinates, using the standard altitude of −0.833° — the value that accounts for atmospheric refraction at the horizon together with the Sun's semidiameter.
Divide the daylight period into eight equal parts to place Rahu Kalam, Yamaganda and Gulika Kalam, each of which occupies a different segment depending on the weekday.
Compute moonrise and moonset by tracking the Moon's altitude across the day and finding where it crosses the horizon, then refining that crossing to the minute.

Transition times — the moment a tithi or nakshatra actually changes — are found by determining when the relevant angle reaches the next exact multiple, not by assuming an average duration.

6. How should you interpret the results?

A panchang describes conditions. It does not issue instructions, and reading it as a list of permissions and prohibitions misses how it is actually used.

Some guidance that experienced practitioners would recognise:

Read the limbs together, not in isolation. A favourable nakshatra during an inauspicious yoga is a mixed picture. No single element decides a day.

Weight them appropriately. For choosing a time, nakshatra generally carries the most weight, followed by tithi. Karana is a refinement. Consulting karana while ignoring nakshatra inverts the traditional priority.

Inauspicious periods apply to beginnings. Rahu Kalam and its counterparts are avoided for starting something — a journey, a purchase, a signing. Work already under way, routine activity and ordinary daily life are not affected. Treating them as hours in which nothing may happen is a modern misreading.

Note the transition times. If the nakshatra changes at 14:20, the character of the morning and the afternoon genuinely differ. This is precisely the information a panchang exists to give, and the element named for the day is only the one in force at sunrise.

Expect regional variation. Whether a month is counted from the new moon (amanta, common in the south and west) or the full moon (purnimanta, common in the north) changes month names and some festival dates, without changing a single astronomical figure. Neither convention is more correct.

Keep it proportionate. A panchang is a traditional framework for timing, offered for guidance and reflection. It is not a substitute for medical, legal or financial advice, and no calculation on this site should be read as a prediction of an outcome.

7. Why does Panchang change for different locations?

This is the question that most often makes people think a panchang is wrong. It is not — location dependence is intrinsic.

Sunrise defines the day. Because the Vedic day begins at sunrise, and sunrise happens at different moments in different places, the boundary between one panchang day and the next moves with you. Delhi and Chennai see sunrise at different times; a tithi that is in force at sunrise in one may already have ended at sunrise in the other. That single difference can shift the tithi assigned to the entire date.

Longitude shifts the clock. The Earth turns 15 degrees an hour, so every degree of longitude moves local solar time by four minutes. Kolkata at about 88°E and Mumbai at about 73°E are 15 degrees apart — a full hour of difference in solar time, even though both keep IST.

Latitude changes day length. How long the Sun stays above the horizon depends on latitude and season. Since Rahu Kalam, Yamaganda, Gulika Kalam and the choghadiya are all fractions of the daylight period, their durations and clock times shift accordingly. Near the equator these segments stay close to 90 minutes year-round; further north they stretch and compress with the season.

The angles themselves barely move. The Sun–Moon longitudes are geocentric, so tithi, nakshatra, yoga and karana change at the same instant worldwide. What differs between places is the local clock time of that instant, and which side of sunrise it falls on.

This is why a printed almanac computed for one city is only approximately right elsewhere, and why the tool on this site asks for your location rather than assuming one.

8. What astronomical data does the tool use?

Positions are not looked up in a stored table or interpolated from a printed almanac. They are computed for the exact instant you request, through a chain of engines tried in order:

Swiss Ephemeris, the reference implementation used by most professional astrology software, accessed natively where the library is available on the server. It derives from NASA JPL's DE431 ephemeris.
VSOP87 and ELP2000, the standard analytical planetary and lunar theories, computed in pure PHP. This requires no native library and is the engine most installations use.
A hosted ephemeris API, where one is configured.
Built-in formulae, as a last resort so the site degrades rather than fails.

On top of whichever engine answers:

Ayanamsa: Lahiri (Chitrapaksha), computed for the date from the Julian Day rather than held as a constant.
Sunrise and sunset: computed from the observer's coordinates at the standard −0.833° altitude.
Moonrise and moonset: computed by converting the Moon's ecliptic position to equatorial coordinates, evaluating its altitude across the day, and bisecting the horizon crossing to the nearest minute. The standard altitude used is +0.125°, the accepted net of refraction, lunar semidiameter and parallax.
Timezone: resolved from the coordinates, so half-hour zones such as IST and Nepal Time are handled correctly rather than rounded.

Results are cached, but the cache key includes the date, coordinates and engine, so a change to any of them produces a fresh calculation rather than a stale one.

9. How accurate are the calculations?

An honest answer has to separate the elements, because they are not equally precise.

Sun and Moon longitudes — very high. Both VSOP87 and the Swiss Ephemeris place the Sun and Moon well within an arcsecond for any modern date. Since a tithi spans 12 degrees and a nakshatra 13°20', an error of this size is thousands of times smaller than the quantity being measured. Tithi, nakshatra, yoga and karana are, for practical purposes, exact.

Transition times — high. The moment a tithi or nakshatra changes is computed from the same longitudes and is reliable to well under a minute.

Sunrise and sunset — good, with a caveat. The algorithm is standard and correct for a sea-level horizon. It does not model your local horizon: mountains, tall buildings or elevation shift observed sunrise by minutes. Refraction also varies with temperature and pressure, which no general algorithm can anticipate. Expect agreement with an observed horizon to within a couple of minutes in flat terrain, and more divergence in hilly country.

Rahu Kalam and the eightfold divisions — as good as sunrise. These are pure arithmetic on the daylight period, so they inherit the sunrise and sunset accuracy exactly and add no error of their own.

Moonrise and moonset — good. Computed rather than estimated, and typically within a minute or two. The Moon is the hardest common rise/set case because its parallax is large and it moves quickly, and the same local-horizon caveat applies. Note that either value may legitimately be absent on a given date: the lunar day runs about 24 hours 50 minutes, so roughly once a month a rise or set falls outside the civil date entirely. A blank is a correct answer, not a failure.

Where you may see differences from another source. Almost all disagreement between panchangs traces to one of four things, none of which is an error:

a different ayanamsa (Raman and KP differ from Lahiri by fractions of a degree, enough to move a boundary);
a different location, including an almanac computed for a fixed reference city;
amanta versus purnimanta month reckoning, which changes month and festival names but no figure;
rounding, where a source reports to the hour rather than the minute.

If you find a discrepancy, checking those four in order will usually explain it.