The animal year changes at Chinese New Year. A leap month repeats a month number; it is not an extra day.
Range: 1901–2100 · Hong Kong Observatory date convention; the year shown is the Gregorian year in which that lunar year began. HKO conversion tables
HKO flags possible one-day astronomical differences near 28 September 2057, 4 September 2089 and 7 August 2097. We follow its published table.
DAY COUNTS & CYCLES
Maya calendars
Long Count units: baktun · katun · tun · uinal · kin. The baktun count continues beyond 13.
Range: 1901–2100 · GMT correlation 584283, Gregorian civil-date correspondence; spellings and traditions vary. Smithsonian: the 2012 date
LUNAR · ARITHMETIC
Islamic tabular civil
A calculated 30-year pattern with a Friday epoch. This is not a local moon-sighting or Umm al-Qura calendar. Religious dates can differ.
Range: 1901–2100 · Daytime date correspondence; the traditional day starts at sunset. Local sunset is not calculated. USNO: civil and observational calendars
LUNISOLAR · FIXED CALENDAR
Hebrew
The year number changes at Tishrei. Leap years include Adar I and Adar II.
Range: 1901–2100 · Daytime date correspondence, before sunset. The Hebrew day begins on the previous evening; no local sunset or observance time is calculated. Hebcal reference converter
Why does New Year move?
A solar calendar follows the seasons. A lunar calendar follows Moon cycles. A lunisolar calendar also adds extra months to keep its months near the same seasons. Those rules give the same day different names.
Chinese New Year is the first day of lunar month 1. Compare three years checked against the Hong Kong Observatory:
The number advances through 1–13 while the day name advances through 20 names. After 260 days, the same pair returns. Use Previous day or Next day to see both move.
Compare a date to see the selected pair.
Number cycle: 1 to 13Day-name cycle: positions 1 to 20
Read the 20 day names in order
Imix
Ik’
Ak’bal
K’an
Chikchan
Kimi
Manik’
Lamat
Muluk
Ok
Chuwen
Eb’
B’en
Ix
Men
Kib’
Kab’an
Etz’nab’
Kawak
Ajaw
Original schematic diagrams, not historical Maya artwork. The selected date is always written above in text. Smithsonian glossary
Sources, methods and data attribution
Chinese dates use a compact ISC-licensed table from yize/solarlunar, independently checked against HKO and corrected at three month boundaries. No browser lunar-calendar formatting is used. Hebrew calculations adapt John Walker’s public-domain Calendar Converter; independent Hebrew fixtures come from Hebcal. Islamic results use the named arithmetic civil rules.
Small open-data reference facts: Hong Kong Observatory, Government of the Hong Kong Special Administrative Region; DATA.GOV.HK, under its Terms and Conditions. These sources do not receive the dates you enter. Method details and fixture provenance are supplied with the project in docs/CALENDAR_SOURCES.md.