Amanta vs Purnimanta: Why Hindu Month Names Differ in North and South India
Is it Kartika or Ashwin? Understand the two Hindu lunar month systems, why festivals keep the same date in both, and how Adhika Maas works.
A friend in Pune says Diwali falls in Ashwin. A friend in Varanasi says it is Kartika. Both are right. India uses two ways of counting lunar months, and knowing the difference clears up a lot of calendar confusion.
Two ways to end a month
- Amanta (ending at Amavasya): the month runs from the day after one new moon to the next new moon. Used in Maharashtra, Gujarat, Karnataka, Andhra Pradesh, Telangana and Tamil Nadu (for its lunar calendar).
- Purnimanta (ending at Purnima): the month runs from the day after one full moon to the next full moon. Used across most of North India: Uttar Pradesh, Bihar, Madhya Pradesh, Rajasthan, Delhi, Punjab, Himachal, Jharkhand and Nepal.
What changes and what doesn't
The Shukla Paksha (bright fortnight) has the same month name in both systems. Only the Krishna Paksha (dark fortnight) differs: in Purnimanta it belongs to the next month.
| Fortnight | Amanta name | Purnimanta name |
|---|---|---|
| Krishna Paksha before Diwali | Ashwin | Kartika |
| Shukla Paksha after Diwali | Kartika | Kartika |
So Diwali's Amavasya is "Ashwin Amavasya" in the Amanta system and "Kartika Amavasya" in the Purnimanta system. The festival date is identical; only the label changes. Our daily panchang shows both names.
How month names are decided
A lunar month is named by the sidereal zodiac sign the Sun occupies when the month begins. In the Amanta system, the month that starts while the Sun is in Meena (Pisces) is Chaitra, the first month of the year. The sequence continues: Vaishakha, Jyeshtha, Ashadha, Shravana, Bhadrapada, Ashwin, Kartika, Margashirsha, Pausha, Magha and Phalguna.
Adhika Maas: the leap month
Twelve lunar months last about 354 days, roughly 11 days short of the solar year. To keep festivals in their seasons, an extra month is inserted about every 32.5 months.
The rule is elegant: if no solar ingress (sankranti) happens between two new moons, that lunar month is Adhika (extra). It takes the name of the following month, so you get Adhika Shravana followed by Nija (regular) Shravana. During Adhika Maas, also called Purushottam Maas, auspicious ceremonies like weddings are generally avoided, while charity, japa and pilgrimage are encouraged. Its two Ekadashis are Padmini and Parama.
Rarely, two sankrantis fall within one lunar month, producing a Kshaya Maas (lost month). This happens only a few times a century.
Which system should you follow?
Follow the one used by your family and region; it decides the names in your vrat kathas and wedding invitations. Festival dates won't change either way, because they are fixed by tithi rather than by the month's name.
Summary
- Amanta months end at new moon; Purnimanta months end at full moon.
- Shukla Paksha names match; Krishna Paksha names are one month apart.
- Festivals fall on the same day in both systems.
- Adhika Maas is added when no sankranti occurs within a lunar month.