Country Calendar Archive

Ancient Egyptian Civil Calendar

One of the earliest well-documented civil calendars. The civil year was divided into three seasons—Akhet, Peret, and Shemu—with four months in each season. Because the classic civil form had no leap day, it drifted through the seasons over long periods.

Ancient Egypt · Solar

Babylonian Calendar

Babylonian timekeeping helped shape later Near Eastern calendrical practice. Month starts were tied to the Moon, while intercalation kept the calendar from drifting too far from the agricultural seasons.

Mesopotamia · Lunisolar

Assyrian Calendar Traditions

Assyrian calendrical traditions formed part of the wider Mesopotamian world of lunar months, seasonal festivals, and state chronology.

Ancient Assyria / Mesopotamia · Lunisolar

Attic Calendar

The Attic calendar was deeply connected to civic and religious life in Athens. Its practical use was local and could involve decisions that make exact modern conversion difficult.

Ancient Athens · Lunisolar

Ancient Hebrew Observational Calendar

Earlier Hebrew calendar practice used observation more directly than the later fixed calculated calendar. Historical month starts and intercalation cannot always be reconstructed with perfect certainty.

Ancient Israel · Lunisolar

Roman Republican Calendar

Before Julius Caesar's reform, Roman calendrical administration could become misaligned with the seasons. Intercalation was not consistently applied, which complicates exact conversion of some historical dates.

Roman Republic · Lunisolar / Civic

Classical

Julian Calendar

The Julian reform regularized the Roman year. Its simple four-year leap cycle is slightly too long relative to the tropical year, which eventually motivated Gregorian reform.

Roman world; later Europe and Christian traditions · Solar

Maya Tzolkʼin

The Tzolkʼin is a 260-day cycle rather than a solar year. It interlocks with other Maya cycles and remains culturally important in some Maya communities.

Mesoamerica · Cycle-based

Maya Haabʼ

The 365-day Haabʼ worked together with the Tzolkʼin to form the larger Calendar Round.

Mesoamerica · Solar-like cycle

Maya Long Count

Unlike the repeating ritual and solar cycles, the Long Count identifies dates within an extended chronological framework.

Mesoamerica · Continuous count

Aztec Tonalpohualli

The tonalpohualli combined number and day-sign cycles and operated alongside a 365-day year cycle.

Central Mexico · Cycle-based

Aztec Xiuhpohualli

The xiuhpohualli structured the annual ceremonial cycle and interlocked with the ritual 260-day count.

Central Mexico · Solar-like cycle

Traditional Chinese Calendar

The Chinese calendar uses astronomical relationships involving lunar phases and solar terms. It remains important for Lunar New Year and other traditional festivals even though the Gregorian calendar is used for civil purposes.

China and Chinese communities worldwide · Lunisolar

Chinese Sexagenary Cycle

The sexagenary system names years and other time units through repeating stem-branch combinations. It is related to, but distinct from, the 12-animal zodiac cycle.

East Asia · Cycle-based

Hebrew / Jewish Calendar

The fixed Hebrew calendar coordinates lunar months with the solar year. Rules for postponements and variable month lengths make it more sophisticated than a simple 19-year leap-month table.

Jewish communities worldwide · Lunisolar

Late Antique to Modern

Coptic Calendar

The Coptic calendar preserves a 13-month structure derived from Egyptian/Alexandrian traditions and is closely related in structure to the Ethiopian calendar.

Coptic Christian communities · Solar

Late Antique to Modern

Ethiopian Calendar

The Ethiopian calendar is a living civil calendar with its own era numbering and 13-month structure. Its year numbering differs from the Gregorian year.

Ethiopia · Solar

Medieval

Armenian Calendar

The traditional Armenian calendar belongs to the family of fixed 365-day systems used in the region and is important in medieval Armenian chronology.

Historic Armenia · Solar

Medieval

Byzantine Calendar

The Byzantine system is best understood as an era and year-numbering framework layered onto the Julian calendar rather than a wholly different month structure.

Byzantine Empire and Orthodox world · Solar / Era

Islamic / Hijri Calendar

Because it is purely lunar, the Hijri year moves through the seasons. Observational practice and calculated systems can produce differences of a day in month starts.

Muslim communities worldwide · Lunar

Tabular Islamic / Civil Calendar

The tabular form provides deterministic dates without requiring local crescent observation, so it can differ from observed religious calendars.

Computational use · Lunar arithmetic

Umm al-Qura Calendar

Umm al-Qura is distinct from a generic tabular Islamic calendar and from local observational determinations used elsewhere.

Saudi Arabia · Lunar

Medieval roots to Modern

Persian / Solar Hijri Calendar

The Solar Hijri year is anchored to the spring equinox and shares its era origin with the Hijri tradition while using a solar, not lunar, year.

Iran and Afghanistan · Solar

Medieval

Jalali Calendar

The Jalali reform is famously associated with a group of astronomers including Omar Khayyam and is an important milestone in Persian solar calendrical history.

Persian world · Solar

Zoroastrian Calendars

There is no single universal modern Zoroastrian calendar practice; communities may use different calendrical reckonings, which should be identified explicitly when converting dates.

Iranian and Parsi communities · Solar / Religious

Hindu Panchanga Calendars

There is no single Hindu calendar. Regional variants can differ in month boundaries, year numbering, whether months begin near new or full moon, and other rules.

India, Nepal, Bali and Hindu communities worldwide · Lunisolar

Ancient era to Modern

Vikram Samvat

Vikram Samvat is an era with multiple calendrical implementations rather than one uniform rule set across South Asia.

India and Nepal · Lunisolar / Solar regional variants

Modern civil use

Nepal Bikram Sambat

Government calendars in Nepal commonly display Bikram Sambat and Gregorian dates together, including public holidays and festivals.

Nepal · Solar

Indian National / Saka Calendar

The Indian National Calendar is a standardized modern civil calendar using the Saka era; it should not be confused with the many regional Hindu calendars.

India · Solar

Early Modern to Modern

Bengali Calendar

The Bengali calendar has undergone reforms, so Bangladesh and West Bengal contexts should not be treated as interchangeable for all historical dates.

Bangladesh and eastern South Asia · Solar

Tamil Calendar

The Tamil calendar is one of several regional Indian calendar traditions and should be presented with its own month names and festival context.

Tamil communities · Solar

Malayalam / Kollam Era Calendar

The Malayalam calendar combines a regional solar calendar with Kollam Era year numbering.

Kerala · Solar

Tibetan Calendar

The Tibetan calendar is calculation-intensive; local traditions and schools may matter for precise festival dating.

Tibetan cultural regions · Lunisolar

Thai Lunar Calendar

Thailand uses the Gregorian calendar for modern civil structure while lunar dates remain important for Buddhist observance and traditional festivals.

Thailand · Lunisolar

Thai Solar / Buddhist Era Calendar

Modern Thai dates often use Gregorian month structure with Buddhist Era year numbering, which is typically 543 years ahead of Common Era numbering for contemporary dates.

Thailand · Solar / Era

Buddhist Era Calendars

“Buddhist calendar” is a family label. Thai, Burmese, Sri Lankan and other traditions should be distinguished when precise rules matter.

South and Southeast Asia · Era family

Balinese Pawukon Calendar

Pawukon is fundamentally different from a normal month-based solar calendar. Multiple week cycles overlap within a repeating 210-day framework.

Bali, Indonesia · Cycle-based

Balinese Saka Calendar

Bali uses more than one traditional time system; the Saka calendar and Pawukon serve different calendrical functions.

Bali, Indonesia · Lunisolar

Early Modern to Modern

Javanese Calendar

The Javanese calendar is a hybrid tradition and is especially notable for combining lunar dating with indigenous cyclic week systems.

Java, Indonesia · Lunar / Cycle hybrid

Korean Dangi / Traditional Calendar

Modern Korea uses Gregorian civil dating, while traditional lunisolar dates continue to matter for holidays and cultural observance.

Korea · Lunisolar / Era

Japanese Era Calendar

Japan uses the Gregorian calendar alongside era names. The current Reiwa era began in 2019, making 2026 Reiwa 8.

Japan · Solar / Era

Minguo / Republic of China Calendar

Minguo year 1 corresponds to 1912 CE. It is an era-numbering system over the Gregorian calendar structure.

Taiwan · Solar / Era

Baháʼí / Badíʿ Calendar

The Badíʿ calendar uses a distinctive 19×19 structure and intercalary days called Ayyám-i-Há. Baháʼí New Year, Naw-Rúz, is tied to the vernal equinox.

Baháʼí communities worldwide · Solar

Nanakshahi Calendar

Nanakshahi calendars are published by Sikh institutions. Because community practice has evolved, specific edition/rules should be stated when precise observance dates are presented.

Sikh communities · Solar

Gregorian Calendar

The Gregorian reform reduced the long-term drift of the Julian calendar and is now the primary civil calendar used internationally, though many communities retain parallel religious or traditional calendars.

Worldwide · Solar