How to convert Nepali and English dates
Why fixed year-and-month subtraction fails for Bikram Sambat dates and how dataset-backed conversion works across 1975 to 2099 B.S.
Practical, verified guidance written for everyday work in Nepal.
1. Confirm which calendar your document uses
In Nepal, official citizenship certificates (nagarikta), land ownership records (lalpurja), academic transcripts, and government notices use the Bikram Sambat (B.S.) calendar. International passports, flight tickets, bank statements, and foreign university applications use the Gregorian (A.D.) calendar, often called the English date in everyday conversation.
2. Why subtracting 56 years, 8 months, and 15 days is not reliable
In the Gregorian calendar, month lengths are fixed (only February changes in leap years). In Bikram Sambat, month lengths are determined by the sun's transit through zodiac signs (sankranti) and can vary between 29, 30, 31, and 32 days from one year to the next. Because the cumulative day count shifts each month, subtracting a fixed offset often produces a date that is 1 to 2 days off.
3. How the Yannis date converter works
Our converter uses a verified year-by-year table of exact Bikram Sambat month lengths from 1 Baishakh 1975 B.S. (13 April 1918 A.D.) through 30 Chaitra 2099 B.S. (13 April 2043 A.D.). It counts the exact number of elapsed days from the epoch anchor to return the true corresponding date and weekday.
4. Best practices for official filings
Always enter the complete 4-digit year, select the month by name to avoid day/month order confusion, and double-check that your converted date matches any secondary date already printed on your citizenship or passport.
5. Why Bikram Sambat New Year and month transitions shift on the Gregorian calendar
Because the sidereal solar year used in Bikram Sambat is slightly longer than the 365.2422-day tropical year used by the Gregorian calendar, and because Gregorian leap years insert February 29 every four years, the exact Gregorian date of 1 Baishakh oscillates between 13 April and 14 April (and occasionally 15 April). Similarly, the last month of the Nepali year (Chaitra) can have 30 days in some years and 31 days in others. This is why a verified lookup table is mandatory for legal and identity documents.
The 12 Bikram Sambat months and their typical day-length ranges
| # | B.S. Month (English & Nepali) | Typical Length (Days) | Gregorian Overlap |
|---|---|---|---|
| 01 | Baishakh (वैशाख) | 30 to 31 days | Mid-April to Mid-May |
| 02 | Jestha (जेठ) | 31 to 32 days | Mid-May to Mid-June |
| 03 | Ashadh (असार) | 31 to 32 days | Mid-June to Mid-July |
| 04 | Shrawan (साउन) | 31 to 32 days | Mid-July to Mid-August |
| 05 | Bhadra (भदौ) | 31 to 32 days | Mid-August to Mid-September |
| 06 | Ashwin (असोज) | 30 to 31 days | Mid-September to Mid-October |
| 07 | Kartik (कात्तिक) | 29 to 30 days | Mid-October to Mid-November |
| 08 | Mangsir (मंसिर) | 29 to 30 days | Mid-November to Mid-December |
| 09 | Poush (पुस) | 29 to 30 days | Mid-December to Mid-January |
| 10 | Magh (माघ) | 29 to 30 days | Mid-January to Mid-February |
| 11 | Falgun (फागुन) | 29 to 30 days | Mid-February to Mid-March |
| 12 | Chaitra (चैत) | 30 to 31 days | Mid-March to Mid-April |
| Epoch Start | 1 Baishakh 1975 B.S. (१ वैशाख १९७५) | 31 days in 1975 Baishakh | 13 April 1918 A.D. |
| Dataset End | 30 Chaitra 2099 B.S. (३० चैत २०९९) | 30 days in 2099 Chaitra | 13 April 2043 A.D. |