An exact Bikram Sambat (BS) to Gregorian (AD) conversion matches a complete date against that BS year’s calendar. The 56/57-year difference is only an estimate: it cannot determine the exact month and day by itself.
Use KhataIN’s BS–AD date converter to enter the year, month and day and see the corresponding date in the other calendar.
Why a full date is needed
The BS year begins around mid-April, not on January 1. A Gregorian year therefore spans two BS years, and the year-number difference changes around the BS New Year. Nepal’s Investment Guide 2024 summarizes the relationship as CE +56 from January to mid-April and CE +57 from mid-April to December. This is a useful orientation, not an exact conversion formula.
Even after identifying the likely BS year, you still need the correct start of the BS month and the number of days in each month for that particular year. A fixed month-length assumption or a calculation that subtracts 56 or 57 from the year can shift the result by days—or place it in the wrong Nepali month.
How to convert BS to AD
- Write down the complete BS date: year, month and day.
- Find the corresponding BS year in a published calendar table.
- Locate the month and count to the requested day using that year’s actual month lengths.
- Read the matching Gregorian date and weekday from the same calendar.
For AD to BS, start with the complete Gregorian date, find where it falls in the BS calendar year, then read the corresponding Nepali month and day. The process is a date-to-date mapping, not an arithmetic change to the year alone.
How KhataIN handles the conversion
KhataIN’s date converter uses its supported BS calendar data to resolve the selected day in the other calendar. The calendar shows the same relationship in context, with BS dates and their Gregorian equivalents. If a date is outside the converter’s supported calendar range, use another verified source for that date rather than extrapolating from the 56/57 rule.
The Gregorian leap-year rule is also independent: Gregorian years divisible by 4 are leap years, except century years not divisible by 400. The U.S. Naval Observatory explains this rule. BS month lengths are determined from the published Nepali calendar for each year, so do not assume that Gregorian leap-year behavior directly determines a BS month or year.
A reliable way to check a conversion
- Include the year, month and day in the source date.
- Confirm that the result is within the tool’s supported year range.
- Check the weekday as a quick consistency check.
- Use the same published calendar source for both dates; do not combine a year offset from one source with month lengths from another.
For background, see what Bikram Sambat is, what the Gregorian calendar is, and the BS-to-AD year chart.