The Nanakshahi (ਨਾਨਕਸ਼ਾਹੀ, nānakashāhī) calendar is a solar calendar that was adopted by the Shiromani Gurdwara Prabhandak Committee to determine the dates for important Sikh events. It was designed by Pal Singh Purewal to replace the Saka calendar and has been in use since 1998. Since 1998, amongst the critics, no-one has come forward with suggestions of specific changes, other than to suggest that the Sikh people should revert back to the Vikrami calendar. The epoch of this calendar is the birth of the first Sikh Guru, Nanak Dev in 1469. New Year's Day falls annually on what is March 14 in the Gregorian Western calendar. 
Hola Mohalla, Bandi Chhor Divas and Guru Nanak Jayanti continue to be celebrated on dates based on the Hindu calendar. All other Sikh religious days are observed in accordance with the Nanakshahi calendar.
The calendar is accepted in about 90% of the gurudwaras throughout the world. There is some controversy about the acceptance of the calendar amongst certain orthodox sectors of the Sikh world. The situation with this calendar is similar to the one at the time of the implementation and acceptance of the Gregorian calendar in the late 1500's. Even after more than 400 years, the Greek Orthodox church, the Ukranian and Russian Orthodox churches still follow the Julian Calendar in their observances. Most people in the Sikh community believe that the calendar is important as it re-affirms the Sikh faith's independence from the Hindu and Muslim faiths. Some orthodox organizations and factions have not accepted it including many orders dating from the time of the Gurus such as Damdami Taksal. Benefits
The new calendar will make life much easier for Sikhs as their holy days will no longer move about the calendar from year to year. Gurpurbs (celebrations devoted to particular Gurus) will now always happen on the same date, and occur once (and once only) in every year. The epoch of this calendar is the birth of the first Sikh Guru, Guru Nanak Dev in 1469. New Year's Day falls annually on what is March 14 in the Gregorian Western calendar.
The calendar doesn't fix the date of all Sikh festivals. Those Sikh festivals, which are celebrated at the same time as similar Hindu religious events, such as Diwali and Hola Mohalla, will still have their dates set by the Vikrami calendar. Features of the new calendar
* a solar calendar
* called Nanakshahi after Guru Nanak (founder of Sikhism)
* year one is the year of Guru Nanak's birth (1469 CE)
* uses most of the mechanics of the Western calendar
* year length is same as Western calendar (365 days 5 hours 48 minutes 45 seconds)
* contains 5 months of 31 days followed by 7 months of 30 days
* leap year every 4 years in which the last month (Phagun) has an extra day NANAKSHAHI SAMAT
by Pal Singh Purewal
Nanakshahi Samat is linked with the Bikrami Samat. Its tithis (sudist vadis) and sangrands are exactly the same as those of the Bikrami Samat. Therefore, it suffers from all the shortcomings of that Samat. The problems with the Bikrami Samat, and with other samats linked to it are as follows:
1. The length of the solar year of the Bikrami Samat does not conform to the tropical year length. The Bikrami year is sidereal year of 365 days, 6 hours, 9 minutes and 10 seconds. The tropical year on which the Common Era calendar is based, has its length as 365 days, 5 hours, 48 minutes and 46 seconds. If the months of any given Era are to recur consistently in the same seasons, then the year length has to be that of the tropical year.
This difference of 20 minutes or so in the two types of years is because of the precession of equinoxes, the yearly retrograde motion of the first point of Aries of the ecliptic. Over a period of time, this difference builds up, and shows in those calendars, which are not based on the tropical year. The seasons in relation to the months begin shifting. This is the reason why Vaisakhi has shifted by 8-9 days from 1469 CE to the present times. The Vaisakhi dates for certain epochs are as follows :
CE Year Vaisakhi Date
1000 22nd March
1469 27th March
1699 29th March
1752 29th March
1753 9th April (due to change from Julian to Gregorian Calendar)
1799 10th April
1899 12th April
1999 14th April
2100 15th April
If Nanakshahi calendar is not de-linked from the Bikrami calendar, this shift will continue, and in 13,000 years Vaisakhi would occur in the middle of October. The seasons will be opposite to those, which are mentioned in the Barah Maha Majh, and Tukhari Banis.
2. The days in the months are not fixed. The number can vary from 31-32 days for the summer months and from 29-30 days for winter months. The rules for determination of Sankrantis, beginning of the months, is complicated and public have to rely on Jantri publishers for such a simple thing as the beginning of a month.
3. The lunar portion of the calendar, according to which most of the religious festivals are fixed, has its share of peculiarities. Since it is based on 12 months of the lunar cycle (full moon to full moon or new moon to new moon), its year length is about 11 days shorter than that of the solar year. Therefore, its year begins 11 days earlier in the following year in relation to the solar year. This is why the Gurpurb dates shift by about 11 days from one year to the other. This is not the end. To keep the lunar year in step with the solar year, every two or three years an extra month is added to the lunar year. This month is called malmas or intercalary month. That lunar year contains 384 or so days. This makes the Gurpurb dates to occur by about 18 or 19 days later when such a month is introduced. The month of Jeth that will occur in 1999 CE will be intercalated, i.e., there would be two months of Jeth, one Sudha and the other Mal. In the malmas or the extra month religious festivals are not celebrated. This is quite a complicated set up, and is also contrary to the philosophy of Gurbani according to which no month in itself is good or bad.
The festivals and Gurpurbs that are celebrated according to the lunar calendar are called movable, and those that are celebrated according to the solar calendar are called fixed. The movable festivals are called as such, because their dates are not fixed in relation to the solar year. From year to year they occur on different dates of the solar year, though their lunar date is the same every year. Gurpurbs of the ten Patshahis are all movable. Vaisakhi and Maghi are fixed festivals. An example of movable celebration is the Parkash Gurpurb of Guru Gobind Singh. It is celebrated on the 7th day of the bright half of the lunar month of Poh (Sudi 7). This lunar date occurs on the following dates of the Common Era and Bikrami Era (solar) during the following eleven years:Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/history-of-sikhism/26646-the-nanakshahi-calendar.html
CE Date Bikrami Date CE Date Bikrami Date
24th Dec., 1990 10th Poh, 2047 12th Jan., 1992 28th Poh, 2048
31st Dec., 1992 17th Poh, 2049 19th Jan., 1994 6th Magh, 2050
7th Jan., 1995 24th Poh, 2051 28th Dec., 1995 13th Poh, 2052
15th Jan., 1997 3rd Magh, 2053 5th Jan., 1998 22nd Poh, 2054
25th Dec., 1998 11th Poh, 2055 14th Jan., 2000 1st Magh, 2056
This Gurpurb did not occur in the CE years 1991, 1993 and 1996. It will not occur in the year 1999 (the year of 300th anniversary of the creation of the Khalsa). It occurred twice in 1992 and 1995; and it will occur twice in 1998. According to the Bikrami calendar (solar) the date of Parkash of Guru Ji is 23rd Poh, 1723 BK. During the above period Gurpurb does not occur on that date. Rather, it occurs in the month of Magh in three years.
A committee, under the aegis of the Institute of Sikh Studies Chandigarh, was formed to study this problem. This committee held meetings at Chandigarh and formulated proposals. These were formally accepted, in principle, in a larger meeting in which about 40 eminent scholars, from universities and other institutions, participated. The main proposals given below were submitted to the S.G.P.C.:
a) Length of the solar year in the Nanakshahi Samat should conform to the more accurate tropical year, instead of the sidereal year, currently being followed.
b) Begin the year from the month of Chet - as in the Baramahas.
c) Fix the number of days in the months as follows:
1. Chet 31
2. Vaisakh 31
3. Jeth 31
4. Harh 31
5. Savan 31
6. Bhadon 30
7. Asu 30
8. Katik 30
9. Maghar 30
10. Poh 30
11. Magh 30
12. Phagun 30/31
d) Fix the beginning of the months in relation to the Common Era calendar as follows:
Month Begins On Month Begins On
Chet 14th March Vaisakh 14th April
Jeth 15th May Harh 15th June
Sawan 16th July Bhadon 16th August
Asu 15th September Katik 15th October
Maghar 14th November Poh 14th December
Magh 13th January Phagun 12th February
With the above scheme, any given date of any month of the Nanakshahi calendar will always occur on the same date of the Common Era calendar, except in the month of Phagun in a leap year when the corresponding dates of Phagun from March 1 to March 13 will differ by 1 day from those of the same month in non- leap years. This is a simple scheme, easier to remember; and the calendar is good forever so that a particular month will have the same season always.
e) Celebrate the Gurpurbs according to the solar dates, and not according to the sudis and vadis of the lunar calendar. Vaisakhi, Maghi, and shaheedi purbs of Sahibzadas are already being celebrated according to the solar dates. If all Gurpurbs were celebrated according to the solar dates, then no complicated calculations for fixing the dates would be required. For example, the birthday of Guru Gobind Singh Ji is:
Poh Sudi 7, 1723 Bikrami (Lunar Calendar)
23rd Poh, 1723 Bikrami (Solar Calendar)
22nd December, 1666 CE (Common Era)
If the Gurpurb is celebrated according to the solar date of Guru Ji's birth on 23rd Poh instead of Poh Sudi 7, then this date will always occur on 5th January each year according to the Nanakshahi Calendar, with proposed reforms.
f) The list of Gurpurbs according to the solar dates is as follows :
Guru Birthdate Gurgaddi Date Jyoti Jot Date
Nanak Dev 1Vaisakh (14 April) from Birth 8 Asu (22 Sept.)
Angad Dev 5 Vaisakh (18 April) 4 Asu ( 18 Sep.) 3 Vaisakh (16 April)
Amar Das 9 Jeth (23 May) 3 Vaisakh (16 Apr.) 2 Asu (16 Sep.)
Ram Das 25 Asu (9 Oct.) 2 Asu (16 Sep.) 2 Asu (16 Sep.)Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/showthread.php?t=26646
Arjun Dev 19 Vaisakh (2 May) 2 Asu (16 Sep.) 2 Harh (16 June)
Hargobind 21 Harh (5 July) 28 Jeth (11 June) 6 Chet (19 March)
Har Rai 19 Magh (31 Jan.) 29 Phagun (12/11Mar) 6 Katik (20 Oct.)
Har Krishan 8 Savan (23 July) 6 Katik (20 Oct.) 3 Vaisakh (16 April)
Teg Bahadur 5 Vaisakh (18 April) 3 Vaisakh (16 Apr.) 11 Maghar (24 Nov.)
Gobind Singh 23 Poh (5 Jan) 11 Maghar (24 Nov) 7 Katik (21 Oct.)
Completion of Granth Sahib Ji: 1 Bhadon (16 August)
First Parkash Granth Sahib Ji: 17 Bhadon (1 September)
Gurgaddi Guru Granth Sahib Ji: 6 Katik (20 October)
Creation of the Khalsa: 1 Vaisakh (14 April)
Hola Mohalla (New Year Day): 1 Chet (14 March)
It must be noted that the dates given above in the Nanakshahi calendar are the original dates of the solar Bikrami year. The corresponding dates of the Common Era are those of the Gregorian Calendar that is now in use in most countries of the world along with local calendars. The conversion to the Common Era dates has been done not according to the Bikrami Calendar, but according to the proposed modified Nanakshahi Samat.
The Bikrami calendar has an error of 1 day in about 71 years. The proposed Nanakshahi calendar will reduce this error to one day in about 3,300 years, but in the case of Nanakshahi calendar this error will automatically be corrected, whenever the correction to the Common Era calendar is made. The new Nanakshahi calendar is simple, rational, more accurate than the Bikrami calendar, and conforms to Gurbani. Sankrantis will occur on the same dates in the CE year, every year. All Gurpurbs will also occur on the same dates every year, with one exception noted above. There will not be any need to consult Jantri publishers to find out when a Gurpurb is to occur.
Shiromani Gurdwara Parbandhak Committee made announcement in October 1997, that S.G.P.C. would adopt this calendar and implement it in the historic year of 1999 CE, when Khalsa Panth celebrates its tercentenary.