What is Bikram Sambat? — Nepal's Official Calendar System Explained

If you have ever looked at a Nepali document and noticed the date reads something like "2082 Baisakh 15" instead of a familiar Gregorian date, you have encountered the Bikram Sambat (विक्रम सम्बत्) calendar. Bikram Sambat, often abbreviated as BS or B.S., is the official national calendar of Nepal — the only country in the world that uses this calendar system as its primary civil calendar.

Every Nepali birth certificate, citizenship card, school exam schedule, tax deadline, and government holiday is dated in Bikram Sambat. Understanding this calendar is essential for anyone living in, working with, or visiting Nepal. This guide covers the complete history, structure, month names, and practical conversion tips you need.

The History and Origin of Bikram Sambat

The Bikram Sambat calendar traces its origin to 57 BCE, making it over 2,080 years old. According to legend, King Vikramaditya (विक्रमादित्य) of the ancient city of Ujjain in central India established this era after defeating the Shakas (Scythian invaders). He proclaimed a new calendar to mark his victory, and the counting of years began from that moment.

While historians debate whether Vikramaditya was a single historical figure or a title used by several rulers, the calendar that bears his name spread across the Indian subcontinent. It was used widely in what is now India, Nepal, and parts of Southeast Asia for centuries.

When India gained independence in 1947, the Indian government adopted the Saka Samvat (Shaka era) as its official civil calendar, beginning from 78 CE. Nepal, however, retained the Bikram Sambat. King Prithvi Narayan Shah, who unified the various kingdoms into modern Nepal in the 18th century, formalized its use as the nation's official calendar. Since Nepal was never colonized by a European power, there was no external pressure to adopt the Gregorian calendar, and Bikram Sambat remained deeply embedded in governance and culture.

How Bikram Sambat Differs from the Gregorian Calendar

The most striking difference is the year count. Bikram Sambat runs approximately 56 years and 8.5 months ahead of the Gregorian (AD) calendar. When the Gregorian calendar reads 2026, the Nepali calendar reads 2082 (until mid-April, when it turns to 2083).

Other key differences include:

• New Year date: The BS new year begins on 1 Baisakh, which falls around April 13-15 in the Gregorian calendar — not January 1. This means a single Gregorian year overlaps with parts of two BS years.
• Variable month lengths: Gregorian months have fixed lengths (28-31 days), but BS month lengths change every year, ranging from 29 to 32 days. They are calculated based on the sun's actual transit through the zodiac signs (rashis).
• Solar basis: The BS calendar is sidereal solar, meaning it tracks the sun's position relative to fixed stars, while the Gregorian calendar is tropical solar, tracking the sun relative to the vernal equinox.
• Lunar integration: While month lengths are solar, religious dates within each month are determined by lunar phases (tithis), making it a lunisolar system for practical purposes.

The 12 Months of the Bikram Sambat Calendar

The Bikram Sambat calendar has 12 months. Each month begins when the sun transits into a new zodiac sign (a point called Sankranti). Below are all 12 months with their Nepali and English names, typical day counts, and approximate Gregorian equivalents:

The summer months (Jestha through Bhadra) tend to be the longest, with 31 or 32 days, while the winter months (Kartik through Falgun) are shorter at 29 or 30 days. This variation reflects the unequal speed of the sun's apparent motion across the ecliptic — it moves faster during the northern hemisphere's winter (Earth is closer to the sun) and slower during summer.

Why Do Nepali Months Have Variable Days?

Unlike the Gregorian calendar, where month lengths were arbitrarily fixed by decree (Julius Caesar and later Pope Gregory XIII), Bikram Sambat month lengths are determined by real astronomical events. Specifically, each month begins at the exact moment the sun crosses from one zodiac constellation to the next — an event called Sankranti.

Because the Earth's orbit is slightly elliptical (not perfectly circular), the sun appears to move through some zodiac signs faster than others. The time between successive Sankrantis ranges from about 29.3 to 31.6 days, which is why BS months can have 29 to 32 days. The Nepal Government's Calendar Determination Committee (पञ्चाङ्ग निर्णायक समिति) publishes the official month lengths each year based on precise astronomical calculations.

Nepali New Year — 1 Baisakh

The Nepali New Year falls on 1 Baisakh, which typically corresponds to April 13, 14, or 15 in the Gregorian calendar. This date marks the sun's transition into the Mesha (Aries) zodiac sign.

Nepali New Year is a public holiday celebrated across the country. In Kathmandu, the Bisket Jatra festival in Bhaktapur is one of the most spectacular New Year celebrations, involving chariot processions, the raising of a ceremonial pole (lingo), and traditional dances. In other regions, families gather for feasts, visit temples, and exchange greetings.

Because the new year starts in mid-April, every Gregorian year spans parts of two BS years. For example, January to mid-April 2026 falls in BS 2082, while mid-April onwards falls in BS 2083.

Converting Between Bikram Sambat and Gregorian Dates

The approximate difference between BS and AD is 56 years and 8-9 months. For a quick mental estimate:

• BS to AD: Subtract approximately 57 from the BS year. For months after mid-April, the AD year is BS minus 57; for months before mid-April, it is BS minus 56.
• AD to BS: Add approximately 57 to the AD year. Before mid-April, the BS year is AD plus 56; after mid-April, it is AD plus 57.

However, because month lengths vary each year, exact date-to-date conversion requires a lookup table or a converter tool. Our Date Converter handles this automatically — just enter a date in either system and get the precise equivalent.

How Bikram Sambat Is Used in Daily Life

The Bikram Sambat calendar is not a relic of the past — it is actively used in virtually every aspect of life in Nepal:

• Government and legal documents: All citizenship certificates, passports, land ownership records, court filings, and official notices use BS dates. Your Nepali birth date is recorded in BS.
• Education: The academic year, examination schedules, school holidays, and university admission deadlines all follow the BS calendar. The school year typically begins in Baisakh (April).
• Fiscal year and taxes: Nepal's fiscal year runs from Shrawan 1 to Ashadh end (mid-July to mid-July). All tax filings, budgets, and financial reporting follow this cycle. See our Nepal Tax Guide for details.
• Salaries and payroll: Monthly salary cycles follow BS months, not Gregorian months. Most employees are paid at the end of each Nepali month.
• Festivals and holidays: Dashain, Tihar, Teej, Chhath, and all other Nepali festivals are determined by BS dates and lunar tithis within the BS framework.
• Daily newspapers and media: Nepali newspapers print the BS date prominently. Television news displays BS dates alongside (or instead of) Gregorian dates.
• Personal milestones: Birthdays, anniversaries, and auspicious events are commonly tracked in BS. Many Nepali people know their birth date in BS but not in AD.

Bikram Sambat Tools on Online Calculator Nepal

Working with two calendar systems can be confusing. Online Calculator Nepal provides free tools to make it effortless:

• Date Converter (BS to AD / AD to BS) — Convert any date between the two calendar systems instantly and accurately.
• Nepali Calendar 2082 — Browse the full BS calendar with festivals, public holidays, and events marked.
• Age Calculator (Nepali) — Calculate your exact age in BS years, months, and days from your BS birth date.

Frequently Asked Questions