Bikram Sambat vs Nepal Sambat vs AD: Key Differences
Nepal is one of the few countries where three calendar systems run side by side in daily life. Government letters carry a Bikram Sambat date, the world's airlines and emails use the Gregorian AD calendar, and the Newar community of the Kathmandu Valley still celebrates its own Nepal Sambat new year. The three rarely line up, and that confuses a lot of people.
The short version: Bikram Sambat is the official solar calendar of Nepal, Nepal Sambat is an older lunar calendar native to the Kathmandu Valley, and AD (Anno Domini) is the international Gregorian system. They start counting from different years and begin their new year in different months.
This guide compares all three on the points that actually matter, origin, era start, new year timing, lunar versus solar reckoning, and where each is used today, so you can read any Nepali date with confidence.
What are the three calendars used in Nepal?
Three calendars coexist in Nepal: Bikram Sambat (BS), the official solar calendar roughly 57 years ahead of AD; Nepal Sambat (NS), a lunar calendar of the Newar people that began in 880 AD; and the Gregorian AD calendar used internationally. Each measures time on its own clock.
Bikram Sambat is what you see on a Nepali passport, school certificate, or newspaper masthead. Nepal Sambat is the heritage calendar of the Kathmandu Valley, recognised as Nepal's national calendar in 2008 yet not used for government administration. AD is the global standard that lets Nepal trade, travel, and communicate with the rest of the world.
If you are still learning the basics of the national system, our explainer on what the Bikram Sambat calendar is covers its structure in full before we contrast it here.
How do Bikram Sambat, Nepal Sambat, and AD compare?
The cleanest way to see the differences is a side-by-side table. The three calendars split on five points: who founded them, which year counts as year zero, when the year turns over, whether they track the sun or the moon, and how official they are in modern Nepal.
| Feature | Bikram Sambat (BS) | Nepal Sambat (NS) | Gregorian (AD) |
|---|---|---|---|
| Origin | Attributed to King Vikramaditya of ancient India | Founded in the Kathmandu Valley, traditionally linked to Shankhadhar Sakhwa | Reform of the Julian calendar by Pope Gregory XIII (1582) |
| Era start (year 1) | Around 57 BC | 880 AD | Year 1 AD (traditional birth of Christ) |
| Offset from AD today | About +56.7 years (2026 AD ≈ 2082-2083 BS) | About -880 years (2026 AD ≈ 1146-1147 NS) | Baseline |
| Calendar type | Solar (sidereal), lunar-solar month names | Lunar (luni-solar) | Solar |
| New year falls in | Baisakh 1, mid-April | Kartik Shukla Pratipada, October-November (Mha Puja season) | 1 January |
| Official use | Official calendar of Nepal for all government work | National calendar (2008), used culturally by Newars | International standard |
Why does each calendar start its year in a different month?
Each calendar begins its year at a moment that mattered to its founders. Bikram Sambat opens on Baisakh 1 in mid-April, near the solar new year when the sun enters Mesh (Aries). Nepal Sambat opens in Kartik, around October or November, and AD opens on a fixed 1 January with no astronomical anchor.
Bikram Sambat: a solar new year in spring
BS is tied to the sun's apparent path. Its new year, Baisakh 1, lands when the sun crosses into the sidereal sign of Mesh, which is why the date drifts slightly each year between roughly April 13 and 15. This is the same Navavarsha celebrated across Nepal. We explain the spring timing in detail in our piece on why Nepali New Year falls in April.
Nepal Sambat: a lunar new year in autumn
NS is a luni-solar calendar, so its months follow the moon and its new year is fixed to a lunar phase, not a fixed date. Nepal Sambat new year falls on Kartik Shukla Pratipada, the first bright day after the Tihar new moon, and Newars mark it with Mha Puja, a ritual worship of one's own body and self. Because it is lunar, the AD date shifts every year.
Which calendar is official in Nepal?
Bikram Sambat is the sole official calendar for government administration in Nepal. Every official document, fiscal year, public holiday list, and citizenship record is dated in BS. Nepal Sambat was declared a national calendar in 2008 to honour the country's indigenous heritage, but it is not used for routine state paperwork.
The Gregorian AD calendar sits alongside both for any international purpose: visas, flight tickets, banking with foreign partners, and academic deadlines abroad. Many Nepalis comfortably hold all three in their heads at once, quoting a birthday in BS, a festival in NS, and a work meeting in AD without a second thought.
Because BS runs the country, knowing the order of its months helps you read any official date. Our guide to the 12 Nepali calendar months from Baisakh to Chaitra walks through each one.
How do you convert between the three calendars?
Converting is not a single fixed sum because BS and NS months do not line up cleanly with AD months. As a rough guide, add about 56 years and 8.5 months to an AD date to get BS, and subtract about 880 years from AD to approximate NS. For exact dates you need a lookup table or a tool.
The BS to AD gap is not a clean number: a BS year straddles two AD years, and each BS month has a variable length of 29 to 32 days set by the sun's motion. That is why a printed or digital converter beats mental math. Our step-by-step walkthrough on how to convert BS to AD dates covers the method and the edge cases.
You can also let the Nepali Calendar (Katigate) app show today's date in BS and AD together, alongside the day's Panchang, so you never have to guess.
Explore more on Nepali Calendar (Katigate)
Frequently Asked Questions
Is Nepal Sambat older than Bikram Sambat?
No. Bikram Sambat counts from around 57 BC, while Nepal Sambat began in 880 AD, so Bikram Sambat is the older era by more than nine centuries. Nepal Sambat is, however, the calendar that originated within Nepal itself rather than ancient India, which gives it deep local significance.
Why is Bikram Sambat about 57 years ahead of AD?
Bikram Sambat starts its count from roughly 57 BC, the era traditionally associated with King Vikramaditya. Since it began counting about 57 years before the AD baseline, every BS year sits roughly 56 to 57 years ahead of the matching AD year, with the exact gap shifting because the BS new year falls in April, not January.
When is Nepal Sambat new year celebrated?
Nepal Sambat new year falls on Kartik Shukla Pratipada, the first bright lunar day after Tihar, usually in October or November. The Newar community celebrates it with Mha Puja, a ritual honouring the self. Because Nepal Sambat is a lunar calendar, the exact AD date changes from year to year.
Which calendar should I use for official work in Nepal?
Use Bikram Sambat for anything official inside Nepal, including government forms, contracts, fiscal records, and certificates. Use the Gregorian AD calendar for international matters such as visas and flights. Nepal Sambat is mainly cultural today, important for Newar festivals rather than state administration.