What is the Bikram Sambat calendar?
Bikram Sambat (विक्रम सम्बत, abbreviated BS) is the official solar calendar of Nepal. It runs roughly 56 years and 8 months ahead of the Gregorian (AD) calendar most of the world uses, and the BS new year falls on 1 Baisakh, around mid-April every year. Twelve months — Baisakh, Jestha, Ashadh, Shrawan, Bhadra, Ashwin, Kartik, Mangsir, Poush, Magh, Falgun and Chaitra — span the year, but each month's length varies from 29 to 32 days depending on solar position.
Why you cannot just subtract 56 from an AD year
The most common BS↔AD mistake is treating the difference as a flat 56 or 57 years. That works only for dates between mid-April and December. For January through mid-April, you need to subtract 57 because the BS year hasn't rolled over yet. Because the new year falls on 1 Baisakh, the safe approach is to use a real converter rather than year arithmetic — that's exactly what the tool above does, sourced from published patro data.
How our BS to AD converter works
Pick a Bikram Sambat date — year, month, day — and the converter returns the matching Gregorian date along with the weekday in English and Devanagari. The same widget toggles to AD to BS conversion with one tap. Every conversion is verified against an internal month-length table covering BS 1970 through 2099 (AD 1913 through 2042), with a known epoch of 1 Baisakh 1970 BS = 13 April 1913 AD. Numerals can be shown in standard digits or in Devanagari (०–९) for documents that need them.
When do Nepalis need a BS to AD converter?
Citizenship cards, passports, school transcripts, academic certificates, employment records, property deeds, court documents, tax filings and the federal budget in Nepal are all written in BS. The moment any of those documents needs to interact with the wider world — a foreign university, a visa application, a bank in another country, an employer abroad — the date has to be converted to AD. A reliable converter is the easiest way to avoid off-by-one errors that can stall a passport application or an academic admission.
Beyond simple date conversion
npdates also includes an age calculator that handles BS or AD birth dates, a date difference calculator for the exact number of days between two events, and a live today's Nepali date page that shows the current BS date and weekday in Asia/Kathmandu time. Developers can use the free REST API to plug BS↔AD conversion into their own apps, and anyone can embed the converter on their website with a single iframe.