The Tamil calendar is a Sidereal time solar calendar used by the Tamil people.S.K. Chatterjee, Indian Calendric System, Publications Division, Ministry of Information and Broadcasting, Government of India, 1998Sewell, Robert and Dikshit, Sankara B.: The Indian Calendar – with tables for the conversion of Hindu and Muhammadan into a.d. dates, and vice versa. Motilal Banarsidass Publ., Delhi, India (1995). Originally published in 1896 It is used in the Indian subcontinent, and other countries with significant Tamil population like Sri Lanka, Malaysia, Singapore, Myanmar and Mauritius. It is used in contemporary times for cultural, religious and agricultural events, with the Gregorian calendar largely used for official purposes.Indian Epigraphy, D.C. Sircar, TamilNet, Tamil New Year, 13 April 2008
Inscriptional evidences from Pagan in Myanmar from the 11th century CE and in Sukhothai in Thailand from the 14th century CE point to South Indian courtiers being tasked with defining the traditional calendar that followed a similar cycle.
The Tamil calendar follows a 60-year cycle similar to the other traditional calendars of India. The Puthandu follows the Nirayana system, and usually falls on 13 or 14 April in the Gregorian year. The new year starts on the date arrived by adding the days corresponding to the 23 degrees of trepidation (oscillation) to the March equinox, when the Sun begins its transition as per the Hindu sidereal calendar. A Tamil calendar year might consist of 365 or 366 days in a year.
After the completion of a cycle of sixty years, the calendar re-starts with the first year of a new cycle. As per the Hindu Panchangam, it represents the year in which Shani Saturn (which takes 30 years to complete one cycle round the Sun) and Brihaspati (Jupiter) (which takes 12 years to complete one cycle round the Sun) come to a same position after 60 years.
The following list presents the current 60-year cycle of the Tamil calendar:
| 01. | பிரபவ | Prabhāva | 1987–1988 | 31. | ஹேவிளம்பி | Hēvilaṃbi | 2017–2018 | |
| 02. | விபவ | Vibhāva | 1988–1989 | 32. | விளம்பி | Vilaṃbi | 2018–2019 | |
| 03. | சுக்ல | Śuklā | 1989–1990 | 33. | விகாரி | Vikāri | 2019–2020 | |
| 04. | பிரமோதூத | Pramadutā | 1990–1991 | 34. | சார்வரி | Śarvarī | 2020–2021 | |
| 05. | பிரசோற்பத்தி | Prachopati | 1991–1992 | 35. | பிலவ | Plava | 2021–2022 | |
| 06. | ஆங்கீரச | Āṅgirasa | 1992–1993 | 36. | சுபகிருது | Śubhakṛt | 2022–2023 | |
| 07. | ஸ்ரீமுக | Śrīmukha | 1993–1994 | 37. | சோபக்ருத் | Śobhakṛt | 2023–2024 | |
| 08. | பவ | Bhava | 1994–1995 | 38. | க்ரோதி | Krodhī | 2024–2025 | |
| 09. | யுவ | Yuva | 1995–1996 | 39. | விசுவாசுவ | Viśvāvasuva | 2025–2026 | |
| 10. | தாது | Dhātu | 1996–1997 | 40. | பரபாவ | Parapāva | 2026–2027 | |
| 11. | ஈஸ்வர | Īśvara | 1997–1998 | 41. | ப்லவங்க | Plavaṅga | 2027–2028 | |
| 12. | வெகுதானிய | Vehudānya | 1998–1999 | 42. | கீலக | Kīlaka | 2028–2029 | |
| 13. | பிரமாதி | Pramāti | 1999–2000 | 43. | சௌம்ய | Saumya | 2029–2030 | |
| 14. | விக்ரம | Vikrama | 2000–2001 | 44. | சாதாரண | Sādhāraṇa | 2030–2031 | |
| 15. | விஷு | Viṣu | 2001–2002 | 45. | விரோதகிருது | Virodhikṛti | 2031–2032 | |
| 16. | சித்திரபானு | Citrabhānu | 2002–2003 | 46. | பரிதாபி | Paritapi | 2032–2033 | |
| 17. | சுபானு | Subhānu | 2003–2004 | 47. | பிரமாதீச | Pramādīca | 2033–2034 | |
| 18. | தாரண | Dhārana | 2004–2005 | 48. | ஆனந்த | Ānanda | 2034–2035 | |
| 19. | பார்த்திப | Partibhā | 2005–2006 | 49. | ராட்சச | Rākṣasaḥ | 2035–2036 | |
| 20. | விய | Viya | 2006–2007 | 50. | நள | Nala | 2036–2037 | |
| 21. | சர்வஜித் | Sarvajit | 2007–2008 | 51. | பிங்கள | Piṅgāla | 2037–2038 | |
| 22. | சர்வதாரி | Sarvadhārī | 2008–2009 | 52. | காளயுக்தி | Kālayukti | 2038–2039 | |
| 23. | விரோதி | Virodhī | 2009–2010 | 53. | சித்தார்த்தி | Siddhidātrī | 2039–2040 | |
| 24. | விக்ருதி | Vikṛti | 2010–2011 | 54. | ரௌத்திரி | Rautrī | 2040–2041 | |
| 25. | கர | Kara | 2011–2012 | 55. | துன்மதி | Dhūnmatī | 2041–2042 | |
| 26. | நந்தன | Nandhana | 2012–2013 | 56. | துந்துபி | Dundubhi | 2042–2043 | |
| 27. | விஜய | Vijaya | 2013–2014 | 57. | ருத்ரோத்காரி | Rudhirōtgāri | 2043–2044 | |
| 28. | ஜய | Jaya | 2014–2015 | 58. | ரக்தாட்சி | Rākṣasī | 2044–2045 | |
| 29. | மன்மத | Manmatha | 2015–2016 | 59. | க்ரோதன | Krodhanā | 2045–2046 | |
| 30. | துன்முகி | Dhuṇmūkī | 2016–2017 | 60. | அட்சய | Akṣayā | 2046–2047 |
| சித்திரை | Chithirai | Chaitra | Spica | April–May | 30–31 |
| வைகாசி | Vaikasi | Vaisakha | Visakam | May–June | 31–32 |
| ஆனி | Āni | Jyestha | Anusham | June–July | 31–32 |
| ஆடி | Ādi | Asadha | Purva Ashadha or Uttara Ashadha | July–August | 31–32 |
| ஆவணி | Āvaṇi | Shravana | Shravana | August–September | 31–32 |
| புரட்டாசி | Purattasi | Bhadrapada | Purva Bhadrapada or Uthiratathi | September–October | 30–31 |
| ஐப்பசி | Aipasi | Asvina | Ashvini | October–November | 29–30 |
| கார்த்திகை | Karthigai | Kartika | Kartikai | November–December | 29–30 |
| மார்கழி | Margazhi | Margashirsha | Mirgashirsham | December–January | 29–30 |
| தை | Tai | Pausha | Pushya | January–February | 29–30 |
| மாசி | Māsi | Magha | Magham | February–March | 29–30 |
| பங்குனி | Panguni | Phalguna | Uttara Phalguni | March–April | 30–31 |
| April–June |
| June–August |
| August–October |
| October–December |
| December–February |
| February–April |
| ஞாயிற்றுக்கிழமை | Nyayitru-kiḻamai | Ravivāra | Surya | Sun | Sunday |
| திங்கட்கிழமை | Tingat-kiḻamai | Somavāra | Chandra | Moon | Monday |
| செவ்வாய்க்கிழமை | Chevvai-kiḻamai | Mangalavāra | Mangala | Mars | Tuesday |
| புதன்கிழமை | Budhan-kiḻamai | Budhavāra | Budha | Mercury | Wednesday |
| வியாழக்கிழமை | Vyaḻa-kiḻamai | Guruvāra | Brihaspati | Jupiter | Thursday |
| வெள்ளிக்கிழமை | Velli-kiḻamai | Śukravāra | Shukra | Venus | Friday |
| சனிக்கிழமை | Sani-kiḻamai | Śanivāra | Shani | Saturn | Saturday |
The months and their significant events and festivals are listed below.
! Month ! Events/festivals | |
| Chithirai | Chitra Pournami, Meenakshi Tirukalyanam, Puthandu |
| Vaikasi | Vaikasi Visakam |
| Aani | Aani Thirumanjanam, Mangani Festival |
| Āadi | Chevvai (Tuesdays) and Velli (Fridays) dedicated to Mariamman; Amavasya, Aadi Perukku, Pooram |
| Āvaṇi | Avani Avittam, Gokulashtami, Ganesh Chaturthi |
| Purattasi | Shani (Saturdays) dedicated to Vishnu; Navarathri |
| Aipasi | Deepavali |
| Karthigai | Thingal (Mondays) dedicated to Shiva; Karthigai Deepam, Kartika Purnima |
| Margazhi | Hanuman Jayanti, Thiruvathirai, Vaikuntha Ekadasi |
| Thai | Pongal, Thaipusam |
| Māsi | Maha Shivaratri, Mahamaham, Poochoriyal |
| Panguni | Panguni Uthiram, Rama Navami |
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