In short
A festival muhurat is calculated by finding where three traditional conditions overlap for your exact city: the right part of the day or night (for Diwali, Pradosh Kaal after sunset), the right rising sign or lagna (for Diwali, the fixed sign Vrishabha), and the right tithi (for Diwali, Amavasya). The Diwali Lakshmi Puja muhurat is the stretch of clock time when all three are true at once, which is why every city gets a slightly different time.
Step 1: sunrise and sunset for your exact city
Every muhurat starts from the Sun. Sunrise and sunset are worked out for your city's latitude and longitude, not for India as a whole.
By the common panchang convention, sunrise is the moment the Sun's upper edge (the upper limb) touches the horizon, with a standard allowance for refraction, the way air bends sunlight. Sunset is the same in reverse.
Step 2: the night and Pradosh Kaal
Pradosh Kaal is the first one-fifth of the night, counted from sunset. The night here means the time from sunset to the next sunrise.
Tradition divides the night into 15 equal muhurtas. Pradosh Kaal is the first three, so night ÷ 15 × 3, which equals night ÷ 5. Nights are longer in winter and in the north, so Pradosh Kaal changes with city and season; it is not a fixed number of minutes. In short, "pradosh kaal kya hai": the first three night muhurtas after sunset in your own city.
Step 3: the Sthir lagna
The lagna is the zodiac sign rising on the eastern horizon at a given moment. As the Earth turns, all 12 signs rise in turn, each taking roughly two hours, depending on the sign and your latitude.
Four signs are called sthir (fixed): Vrishabha, Simha, Vrishchika and Kumbha. By tradition, a puja done in a fixed lagna is meant to bring steadiness, and for Diwali Lakshmi Puja the custom is to choose Vrishabha lagna, which rises in the early evening around Diwali. We use the sidereal zodiac with the Lahiri ayanamsa, the standard choice in Indian panchangs.
Step 4: the tithi must prevail
A tithi is a lunar day, measured by the angle between the Moon and the Sun (see tithi and vaar explained). For Diwali, the rule is that Amavasya must prevail during the muhurat. If Amavasya has not begun yet, or has already ended, during Pradosh Kaal, the evening does not qualify.
Putting it together
| Part of the Diwali muhurat | The rule |
|---|---|
| Sunset | Sun's upper limb at the horizon, standard refraction, for your city |
| Pradosh Kaal | Sunset to sunset + one-fifth of the night (3 night muhurtas) |
| Sthir lagna | Vrishabha rising, sidereal, Lahiri ayanamsa |
| Tithi | Amavasya prevailing |
| Muhurat | The overlap of all three |
Usually Vrishabha rises a little after sunset, so the muhurat starts later than Pradosh Kaal. In some cities Pradosh Kaal ends before the lagna does, and then Pradosh Kaal sets the end time.
Muhurat follow traditional rules. They help a family plan a puja together; they are not a guarantee of any result.
Why the time is different in every city
India uses one clock, IST, but the Sun does not. Three things move the time:
- Longitude. Sunset comes earlier in the east and later in the west, on the same IST clock.
- Latitude. Northern cities have longer winter nights, so Pradosh Kaal is longer, and signs rise at different speeds.
- The lagna. The rising sign depends on your local position, so Vrishabha rises at a different clock time in each city.
That is why a search like "Diwali puja time today" should always be answered for your own city. Our Diwali 2026 muhurat page lists 70 cities.
Why two panchangs can differ by a few minutes
When two careful panchangs differ by a few minutes, the reason is usually a convention, not a mistake:
- whether sunrise is taken at the Sun's upper edge or its centre, and how refraction is handled
- the ayanamsa (the sidereal correction) used for the lagna
- how Pradosh Kaal is defined (one-fifth of the actual night, or a fixed length)
- the exact coordinates taken for the city, and how times are rounded
How SachAstro calculates this
We use our own engine, built on NASA JPL DE440 planetary data through Skyfield. Our conventions are fixed and written down: sunrise and sunset use the Sun's upper limb with standard refraction; moonrise and moonset use the centre of the Moon's disc, topocentric; the tithi is the Moon−Sun elongation divided by 12°; the lagna is sidereal with the Lahiri ayanamsa. Times are rounded to the nearest minute, in IST. On 29 October 2026 we checked our results against a leading public panchang for 10 cities, and all were within 2 minutes.
Frequently asked questions
What is Pradosh Kaal?
Pradosh Kaal is the first one-fifth of the night after sunset, which tradition counts as three night muhurtas. Its length depends on your city and the season.
Why is Vrishabha lagna used for Lakshmi Puja?
Vrishabha is one of the four fixed (sthir) signs, and tradition holds that worship in a fixed lagna brings steadiness. It also rises in the early evening around Diwali, inside Pradosh Kaal.
Why is the Diwali muhurat different in Mumbai and Kolkata?
The Sun sets much earlier in Kolkata than in Mumbai on the same IST clock, and the lagna rises at a different clock time too. So the overlap falls at a different time in each city.
Why does my panchang show a time a few minutes different?
Small differences usually come from conventions: how sunrise is defined, the ayanamsa, how Pradosh Kaal is measured and how times are rounded. Our times were within 2 minutes of a leading public panchang in our check.
Is a muhurat a guarantee of good results?
No. A muhurat is a traditional rule for choosing a time, not a promise about outcomes. Festival times for 70 cities are free on SachAstro, with no sign-in.