How Many Days in a Lunar Month? Chandra Maas 2026–28

The textbook figure for a lunar month is about twenty-nine and a half days, and real months scatter around it. A chandra maas counted the amanta way, from one new moon (amavasya) to the next, ran between 29.28 and 29.81 days across the 36 months from January 2026 to December 2028. The average of those 36 came to 29.51. Counted the purnimanta way, from full moon to full moon, the 37 months in the same stretch ran 29.39 to 29.70 days.

Every figure here was measured from the site’s computed new and full moons, not divided out from an average. The page gives lengths and opening dates only, not the clock time of any new moon or tithi; for a given day’s tithi, use the panchang.

Every Amanta Month, January 2026 to December 2028

Each month is named, in the amanta reckoning, by the sign the Sun holds at the new moon that opens it. The sunrise column counts the sunrises at New Delhi that fall inside the month, where the daily panchang table covers it.

The shortest month in the run is the one opening 15 June 2026, at 29 d 6 h; the longest opens 9 December 2026, at 29 d 19 h. The gap between them is more than 12 hours. Of the 24 months the daily table covers, 12 held 29 sunrises and 12 held 30. Since every month in the table is longer than twenty-nine days and shorter than thirty, and sunrises come about a day apart, each one holds either twenty-nine sunrises or thirty.

Why Some Months Run Long

A month ends when the Moon has gone once round the zodiac and is back in line with the Sun. The faster the Sun is moving, the farther the Moon must travel to come back into line. The Sun’s apparent speed through the zodiac is not constant: at its 2026 ingresses it moved 1.0188° a day entering Capricorn in January and only 0.9544° entering Cancer in July. That is why the six longest months in the table all open between November and February, and the six shortest between May and August.

The Moon’s own speed varies far more than the Sun’s, so a month also runs long or short according to how fast the Moon happens to be moving around the new moons that bound it. That is why no two years in the table repeat exactly. The same unevenness decides how long the Moon stays in each nakshatra; how long a nakshatra lasts measures it. Measured between full moons instead, the range over the same years is a little narrower, 29.39 to 29.70 days.

How Long Is a Tithi?

A month always has thirty tithis, because a tithi is defined as twelve degrees of the Moon’s lead over the Sun, and a month is the full 360°. What varies is how long each one takes. Across the 741 complete tithis of 2026–27, the shortest lasted 20.07 hours and the longest 26.72. The average, 23.62 hours, is a little under a day, so thirty tithis fit in about twenty-nine and a half days.

Because a tithi can be shorter than the time from one sunrise to the next, it sometimes begins after one sunrise and ends before the next, and no sunrise ever carries its name. That is a kshaya tithi. A tithi longer than a day can hold two sunrises in a row, a vriddhi tithi. Reading the sunrise tithi at New Delhi for every day of 2026–27, 34 tithis were kshaya and 23 were vriddhi. That is why a month can have thirty tithis but only twenty-nine sunrises, and why a festival fixed to a tithi can move by a day between cities. How a missing or doubled tithi moves a Hindu birthday is worked through in the tithi birthday table.

Twelve Lunar Months Against a Solar Year

Any twelve consecutive months in the table add up to between 353.97 and 354.72 days. The Sun’s return to sidereal Aries took 365.25 days from 2026 to 2027 and 365.26 from 2027 to 2028. Twelve lunar months therefore fall short of the solar year by about eleven days, and without a correction the month names would drift away from the seasons. The correction is the adhika maas, the extra month inserted when two new moons fall while the Sun is in one sign. The table above has one, Adhika Jyeshtha in 2026. The site’s adhika table lists 10 from 2020 to 2045; the next adhik maas gives every one and how the rule finds it.

Amanta and Purnimanta: Same Months, Different Edges

The north Indian almanacs end the month at the full moon (purnimanta); those of Maharashtra, Gujarat, Goa, Karnataka, Telangana and Andhra Pradesh end it at the new moon (amanta). Both name the bright fortnight alike. The dark fortnight that an amanta almanac files under one month, a purnimanta almanac files under the next, so the same Krishna paksha tithi carries two month names. The Tamil, Malayalam, Bengali, Odia and Assamese calendars are solar instead: their month runs from one solar ingress to the next, which in 2026–28 took 29.45 to 31.45 days. The shortest solar month is briefer than the longest lunar one, but twelve solar months always make exactly the solar year, so a solar calendar never needs an extra month. For the start and end dates of a named month in a given year, see the month pages such as Margashirsha 2026 and Paush 2026. In Hindi: चन्द्र मास कितने दिन का होता है? अवधि 2026–28.

In Brief

• Amanta month: 29.28 to 29.81 days in 2026–28, average 29.51
• Purnimanta month: 29.39 to 29.70 days over the same years
• Sunrises in a month: 29 or 30 in every month of 2026–27
• Tithi: 20.07 to 26.72 hours, thirty to every month
• Twelve months: about 354 days, some eleven short of the solar year, which the adhika maas makes up