Leap years and leap months
Check whether a year is a leap year, list the leap years in a range, and see each year’s Chinese leap month and the length of its solar and lunar years.
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Runs in this page in your browser; nothing is uploaded.
About this tool
Check whether a year is a leap year, list every leap year in a range, or see which Chinese lunar years have a leap month. Use it when planning around 29 February, checking a date in an old document, or finding out whether next year’s lunar calendar has 13 months.
The single-year check applies the Gregorian rule to any whole year. The range table covers 1901 to 2099 and shows, for each year, whether it is a Gregorian leap year, its lunar leap month and the number of days in its solar and lunar years. It runs in your browser and nothing is uploaded.
How to use it
- Type a year into “Year” to see whether it is a leap year (366 days) or a common year (365 days).
- Set “From” and “To” to list the leap years between them. Both are limited to 1901–2099.
- Read the table for each year’s “Leap year”, “Lunar leap month”, “Solar days” and “Lunar days”. The current year is highlighted.
Common questions
Why is 1900 not a leap year when 2000 is?
A year divisible by 4 is a leap year, except years divisible by 100, which are leap years only if they are also divisible by 400. 1900 is divisible by 100 but not by 400; 2000 is divisible by 400.
What is a lunar leap month?
Some lunar years have 13 months: one month is followed by a leap month with the same name, such as 闰六月, the leap sixth month, in 2025. The table shows which month it is, written as “month 6” in English, and a dash when there is none.
How many days does a lunar year have?
A lunar year runs from one Chinese New Year to the next. Between 1901 and 2099, years with a leap month have 383 to 385 days and the others 353 to 355, as shown in “Lunar days”.
Which lunar year does each row show?
The lunar year that begins at Chinese New Year in that Gregorian year. Its leap month and length belong to that lunar year, which ends at the next Chinese New Year.
Can I check years outside 1901–2099?
The “Year” check works for any whole year and uses the Gregorian rule even for years before that calendar was adopted. The range and the lunar columns are limited to 1901–2099.
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