If you deal with Nepali documents, you deal with two calendars. The English or Gregorian calendar (AD) is used internationally. The Bikram Sambat (BS) calendar is the official Nepali calendar, and it appears on citizenship papers, land records, school certificates, invitations and government forms.
Converting between them looks like it should be a simple formula. It is not, and the reason is worth understanding: BS months do not have fixed lengths.
What Bikram Sambat is
Bikram Sambat is the era used by Nepal’s official calendar. Its year begins with the month Baisakh, which starts in mid-April. The era starts in 57 BC, which is why BS is ahead of AD rather than behind it.
The rough offset is 56 years and 8 months. Because the BS year changes in mid-April, the offset is about 57 years before Baisakh 1 and about 56 years after it. That is why a date in January and a date in June of the same AD year can fall in different BS years.
For example, 1 November 2026 is २०८३ कार्तिक १५, आइतबार in BS. The converter on this site shows the Devanagari numerals, the month name and the weekday together, which is how Nepali documents usually write a date.
Why the months vary
A Western calendar has a fixed rule: 30 or 31 days, with February taking 28 or 29. You can calculate any date from a formula.
Bikram Sambat does not work that way. Each BS month has 29, 30, 31 or 32 days, and the length of each month is set every year from astronomical calculations in the official panchang. There is no simple rule that produces the pattern.
The practical consequence is that every converter carries a table of official month lengths. It cannot compute them from a formula, and it cannot safely extrapolate far into the future.
Here is the pattern for BS 2083, the year that begins in April 2026:
| # | Month | Days | First day (AD) |
|---|---|---|---|
| 1 | Baisakh | 31 | 14 April 2026 |
| 2 | Jestha | 31 | 15 May 2026 |
| 3 | Asar | 32 | 15 June 2026 |
| 4 | Shrawan | 31 | 17 July 2026 |
| 5 | Bhadra | 31 | 17 August 2026 |
| 6 | Aswin | 31 | 17 September 2026 |
| 7 | Kartik | 30 | 18 October 2026 |
| 8 | Mangsir | 29 | 17 November 2026 |
| 9 | Poush | 30 | 16 December 2026 |
| 10 | Magh | 29 | 15 January 2027 |
| 11 | Falgun | 30 | 13 February 2027 |
| 12 | Chaitra | 30 | 15 March 2027 |
Now compare neighbouring years. BS 2081 gives Jestha 32 days and Asar 31, ends with a 31-day Chaitra and has 366 days in all. BS 2082 happens to repeat the 2083 pattern exactly, and BS 2084 changes again (Aswin 30, Mangsir 30, Poush 29). The total is sometimes 365 days and sometimes 366, and the individual months move around with no cycle you can rely on.
Why this matters in practice
If you assume every BS month has 30 days, you will be wrong within a month or two. If you assume a BS year is exactly 365 days, you will drift. A date that looks plausible can be off by a day or more, which is enough to miss a deadline or misstate a birth date.
This is also why you should not convert by adding a fixed number of years. “BS minus 57” is a rough guide, not a conversion. The month and day have to come from the calendar table.
How to convert
Use the Nepali date converter. It works in both directions:
- AD → BS: pick the English date and read the Nepali date with Devanagari numerals, the month name and the weekday.
- BS → AD: pick the BS year, month and day and read the English date.
The converter supports BS 2000 to 2090, which is 14 April 1943 to 13 April 2034. The range ends there because official month lengths have not been published further ahead. Open datasets disagree about later years, so the tool reports a range error instead of guessing. If you need a date after 13 April 2034, check the official calendar when it is published.
The top of the page also shows today’s BS date. It reads your device clock, converts it to Nepal time (UTC+5:45) and displays the result, so it is correct whenever you open the page.
Reading a Nepali date
A Nepali date usually appears as year, month, day, for example २०८३ कार्तिक १५. The digits are Devanagari: ० १ २ ३ ४ ५ ६ ७ ८ ९.
When you copy a date into a form or a document, keep the month name with it. Writing only the numbers can be ambiguous to someone used to the Western order.
Weekdays are written in Nepali too: आइतबार (Sunday), सोमबार (Monday), and so on. Saturday (शनिबार) is the weekly holiday in Nepal, and calendars usually mark it in red.
Common uses
- Official forms. Citizenship, land, school and migration paperwork often asks for a BS date.
- Deadlines. Nepali offices set deadlines in BS, and the corresponding AD date is not obvious.
- Age calculations. A birth date in BS has to be converted before it can be compared with an AD date.
- Travel and events. Invitations and notices commonly give the BS date, sometimes with the AD date beside it.
- Records and archives. Old documents may use BS years that are well outside living memory.
A note on accuracy
The converter uses published month-length tables for BS 2000–2090. Those tables are not a substitute for the official panchang in a legal or administrative dispute. For anything binding, confirm the date with the issuing office or the official calendar.
That said, for everyday use, the table is far more reliable than arithmetic. Use the converter, check the month name, and keep a copy of the result.
The short version
Bikram Sambat is Nepal’s official calendar, it begins in mid-April, and its months have 29 to 32 days that change from year to year. There is no formula, only a table. Convert with the Nepali date converter, read the month name as well as the number, and do not rely on a fixed year offset. For other Nepali tools, including Preeti conversion and number-to-words, see the Nepali hub.