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Nepal conversions guide

AD to BS and BS to AD Date Conversion: Range and Accuracy Explained

Convert AD and Bikram Sambat dates from a bounded calendar table—not a guessed year offset.

By Dhruba PoudelReviewed 2026-09-29Tool runs at tools.dhrub.com.np

Can an AD date be converted to BS by adding 56 or 57 years?

No. Bikram Sambat months have varying lengths and New Year does not start on 1 January, so adding a fixed year offset produces wrong dates. The converter uses a day-by-day relationship anchored to a bounded table of real BS month lengths and refuses dates beyond that table.

How to use the tool

Choose AD to BS or BS to AD

Select the direction that matches the date printed on your source.

Enter a complete valid date

Use the displayed year, month and day fields; impossible dates are rejected.

Verify important dates

For deadlines, payroll, legal records or official forms, compare the result with the issuing authority’s calendar.

At a glance

Supported AD range
13 April 1918 through 13 April 2043
Supported BS range
1975-01-01 through 2099-12-30
Method
Bounded month-length table with a known anchor
Fixed 56/57-year offset
Not used

Why the supported range is explicit

A dependable calendar converter must know how many days are in every supported BS month. The current local table covers BS 1975 through BS 2099. Dates outside it are not extrapolated because future or historical month patterns cannot safely be guessed.

The corresponding Gregorian boundary is 13 April 1918 through 13 April 2043. Boundary dates are included, and invalid day values are rejected before conversion.

  • Use ISO-style numeric output when copying data between systems.
  • Keep the original calendar label—AD or BS—beside a stored date.
  • Do not treat a date conversion as advice about a legal filing deadline.
  • Check public holidays separately; conversion does not identify office closures.

Calendars, holidays and official use

A calendar conversion answers which civil date corresponds to another date. It does not decide the legal effective date of a notice, a banking value date or the last day to submit an application. Those questions can depend on time zones, public holidays and the responsible authority’s rules.

Kathmandu Metropolitan City publishes an official-facing BS/AD calendar, and Nepal government bodies publish holiday notices. These are useful comparison sources for dates in their covered period.

Important limitations

  • Dates outside the documented range are refused rather than estimated.
  • Holiday, festival and auspicious-time information is not generated by the converter.
  • A converted date does not determine a legal deadline or office opening day.
  • Critical results should be checked against the responsible authority.

Questions people ask

Why is the BS year about 56 or 57 years ahead?

The calendar eras and New Year dates differ, so the apparent year difference changes within a Gregorian year. It is not enough to determine the month and day.

Can I convert a date after BS 2099?

Not with this data release. The tool refuses dates it cannot support rather than extrapolating unknown month lengths.

Does the result include Nepali public holidays?

No. Holiday schedules are separate official datasets and can change by government notice.

Primary and project sources

  1. Calendar (BS / AD) — Kathmandu Metropolitan CityOfficial city calendar presenting corresponding BS and AD dates.
  2. Public holidays — Ministry of Home Affairs, NepalExample of official holiday publication separate from date conversion.
  3. Nepal Panchanga Nirnayak Samiti — Nepal Panchanga Nirnayak SamitiOfficial calendar committee notices.
  4. nepali-date-converter source — Remote MergeMIT-licensed upstream month-table implementation adapted for the bounded local converter.