BS to AD Converter

How to Use This Tool

1. Pick the BS yearChoose any year from 2000 to 2083 BS.
2. Pick the month and dayMonths are listed by name in English and Nepali; days run to that month’s real length.
3. Read and copy the AD dateCopy the date in words or in YYYY-MM-DD form for a form or spreadsheet.

How It Works

There is no formula for Bikram Sambat. Each month runs 29 to 32 days, and how long a given month runs in a given year is published in the Nepali almanac (पञ्चाङ्ग). The converter holds those lengths for every month from 2000 to 2083 BS, counts how many days your date sits after 1 Baisakh 2000 BS, which was 14 April 1943, and adds that count to 14 April 1943. Every row of the table agrees between two independently built open-source calendars, and the result is checked against dates known from history: 3 Asoj 2072, the day the constitution was promulgated, converts to 20 September 2015.

Worked Examples

When You Need an AD Date

Nepali documents are dated in Bikram Sambat, the country’s official calendar: citizenship certificates (नागरिकता), birth registrations, school certificates, land records and most government letters. American forms want the Gregorian date. A birth date copied from a citizenship certificate onto a visa, school or employment form has to be converted first, and an off-by-one error there is the kind that sends paperwork back.

Once the date is in AD you can use it directly: work out an age from the converted birth date, or turn it into a Unix timestamp if a system wants one. Going the other way, from an American date to a Nepali one, is what the AD to BS converter is for.

Where Each Month of 2083 BS Begins

The current BS year, 2083, began on 14 April 2026. Its months start on these dates. Month lengths change from year to year, so a table like this is only true for the year it names.

The Fiscal Year: Shrawan to Asar

Nepal’s fiscal year (आर्थिक वर्ष) runs from 1 Shrawan to the last day of Asar, roughly mid-July to mid-July, and is written with both years, such as 2083/84. A date in Baisakh, Jestha or Asar therefore belongs to the fiscal year that began the previous Shrawan: 20 Asar 2083 is in fiscal year 2082/83, while 1 Shrawan 2083 starts 2083/84. The converter shows the fiscal year with every result, because tax, salary and audit paperwork in Nepal is filed against it.

Why Festival Dates Move on the AD Calendar

Bikram Sambat months are solar: each one begins when the sun enters the next sign of the zodiac, which is why 1 Baisakh always lands on 13 or 14 April and 1 Magh, Maghe Sankranti, always lands in mid-January. A festival tied to one of those solar dates barely moves on either calendar.

Most of the big festivals are not solar. Dashain, Tihar and Teej are set by tithi, the lunar day, so they follow the moon. A lunar year is about eleven days shorter than a solar one, which is why Dashain can fall in late September one year and late October another, moving on the BS calendar as well as the AD one. Converting a festival date from one year therefore tells you nothing about the next year: look each year up in that year’s published calendar, then convert the date you find. To plan around the gap, count the days between two converted dates.

The Twelve Months, in Nepali and in Formal Writing

Everyday Nepali uses the short month names in the first column. Government notices and older documents often use the Sanskrit forms in the second, so the same month can appear as साउन on a calendar and श्रावण on a letter. Both refer to the same month and convert identically.