TL;DR: The Indian lunar calendar tracks the Moon’s phases. A tithi (lunar day) is ~12° of Moon–Sun separation (≈0.95 solar days). Two fortnight halves—Śukla (waxing) and Kṛṣṇa (waning)—make a month (māsa). Because 12 lunar months are ~11 days shorter than a solar year, an extra adhika māsa (leap month) is inserted ~every 32–33 months to realign seasons. With five daily “limbs”—tithi, vāra, nakṣatra, yoga, karaṇa—the pañchāṅga helps you time rituals, fasts, and festivals.

Lunar Calendar: A Practical Guide to Tithis, Months, and Festivals

If the solar calendar tells you where the Earth is, the lunar calendar tells you how the mind feels. Festivals, fasts, and rites across India key off the Moon, and the classic pañchāṅga turns astronomy into a daily planning tool.

Who this is for (and what you'll get)

Readers: Practitioners, families, and students who want a reliable, no-jargon explainer.
Intent: Informational with practical how-tos.
Promise: In 10 minutes you’ll understand tithis, pakshas, months, leap months, pañchāṅga basics, and how to read dates in Amānta vs. Pūrṇimānta systems.

The Building Blocks (fast map)

Synodic month: New Moon to New Moon ≈ 29.53 days.
Tithi (lunar day): Each step of 12° Moon–Sun elongation; 30 tithis per lunar month.
Paksha (fortnight): Śukla (Waxing; New Moon → Full) and Kṛṣṇa (Waning; Full → New).
Māsa (month): Named by the nakṣatra near the Full Moon (e.g., Chaitra, Vaiśākha).
Vāra: Weekday (Ravivāra → Śanivāra).
Pañchāṅga’s five limbs: Tithi, Vāra, Nakṣatra, Yoga, Karaṇa.

Why tithis feel slippery: A tithi can start/end at any clock time and may skip or repeat on civil dates because its length is not fixed to 24 hours.

Two Month Styles: Amānta vs. Pūrṇimānta

Amānta (South & West India): Month ends at New Moon (amāvāsyā). Śukla Paksha begins the new month.
Pūrṇimānta (North & East India): Month ends at Full Moon (pūrṇimā). Kṛṣṇa Paksha begins the new month.

Practical tip: The festival day usually matches nationwide (based on the same tithi), even if the month name differs by region due to the style.

Why Leap Months Happen (Adhika Māsa)

Solar year ≈ 365.24 days; 12 lunar months ≈ 354.37 days → ~11-day gap.
To keep months in the right season, calendars insert Adhika Māsa when no Sun–sign ingress (saṅkrānti) occurs during a lunar month.
This occurs roughly every 32–33 months. The leap month takes the name of the following normal month (e.g., Adhika Āṣāḍha).
Kṣaya (missing) month is rare: when two saṅkrāntis fall in one lunar month, a named month can drop out once in long cycles.

Reading a Pañchāṅga (step-by-step)

Date & Place: Pañchāṅga is location-dependent (Moonrise/Moonset, sunrise).
Tithi: Note today’s tithi and its end time (e.g., Daśamī till 14:12).
Vāra: Weekday for routine and vows (e.g., fasts on Ekādaśī if within sunrise–sunrise window).
Nakṣatra: The lunar mansion the Moon occupies; useful for muhūrtas and personal observances.
Yoga: Sum of longitudes of Sun+Moon → auspicious/inauspicious yogas for timing.
Karaṇa: Half-tithis; important for specific rites (e.g., Bhadra cautions).
Sunrise anchor: Many rules apply sunrise to sunrise; check if a tithi prevails at sunrise for fasts/festivals.

Festival rule of thumb: A festival usually falls on the tithi that prevails at local sunrise (there are exceptions like Dīpāvalī tied to amāvāsyā evening). Always check local pañchāṅga notes.

Month Names (at a glance)

Chaitra, Vaiśākha, Jyeṣṭha, Āṣāḍha, Śrāvaṇa, Bhādrapada, Āśvina, Kārtika, Mārgaśīrṣa/Agrahāyaṇa, Pauṣa, Māgha, Phālguna.
(Regional spellings vary; Adhika may prefix any of these during leap years.)

Popular Observances & Anchors

Ekādaśī: 11th tithi; fast devoted to preservation (sattva), observed twice monthly (Śukla/Kṛṣṇa).
Pūrṇimā/Amāvāsyā: Full/New Moon baths, tarpaṇa, charity; anchors many vows.
Navarātri: Begins Śukla Pratipadā of Āśvina (Pūrṇimānta) / Kārtika (Amānta); nine nights of worship.
Mahāśivarātri: Kṛṣṇa Caturdaśī of Māgha/Phālguna (regional naming differs by style).
Dīpāvalī: Amāvāsyā of Kārtika (evening focus).

Note: The tithi logic is the unifier; month-names may vary by region while the observed day aligns.

Panchāṅga vs. “Just Moon Phases”

Beyond phases: The pañchāṅga integrates five calculations, not only Full/New Moons.
Locality matters: Longitude/latitude shift tithi boundaries and moonrise/moonset.
Civil vs. ritual day: Civil dates run midnight–midnight; pañchāṅga often anchors to sunrise, which changes some observances.

How It Relates to Solar Calendars

Many Indian regions run luni-solar systems: lunar months keyed to solar seasons via saṅkrānti and adhika māsa.
Solar-only almanacs (e.g., Tamil, Malayalam) use solar months; festivals still often follow lunar tithis, so both are consulted.

Get Started (practical mini-guide)

Pick a reliable pañchāṅga app/site that supports your city.
Track three items for a week: today’s tithi, nakṣatra, and whether tithi spans sunrise.
Observe personal effect: energy, focus, sleep—see how lunar rhythm interacts with routine.
Mark repeats: Ekādaśī, Pūrṇimā, Amāvāsyā—plan simple vratas or reflections.

Quick Glossary

Tithi: Lunar day (12° separation).
Paksha: Fortnight half (Śukla/Kṛṣṇa).
Māsa: Lunar month (named by Full Moon’s nakṣatra).
Adhika Māsa: Intercalated leap month.
Saṅkrānti: Sun’s ingress into a new sign.
Nakṣatra: 27/28 lunar mansions.
Yoga/Karaṇa: Pañchāṅga factors shaping the day’s quality.
Amānta/Pūrṇimānta: Month ending at New/Full Moon.

SEO & Distribution Bits

Primary keyword: “Lunar Calendar”
Supporting entities: “Pañchāṅga”, “Tithi”, “Paksha”, “Adhika Māsa”, “Nakṣatra”, “Amāvāsyā”, “Pūrṇimā”.
Meta title (≤60): Lunar Calendar Guide: Tithis, Months, Festivals
Meta description (≤155): Learn the Indian lunar calendar—tithis, pakshas, leap months, and how to read a pañchāṅga for festivals and fasts.

What to do next

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Author

VedaSeek Team — researchers and practitioners making traditional timekeeping simple and useful for modern life.