Chinese Calendars

This page describes how the Chinese lunar calendar system works. In this calendar section we have a display of the Chinese calendar for the whole current month showing all festivals as well as a whole year calendar for 2024 and 2025.

Chinese Calendars

It has always been vital to know the accurate date in the year so everything is done at the appropriate time. Many activities are keyed to the calendar: when seeds must be planted; grain harvested; fruit gathered and sheep moved to upland. So from the earliest times it has been essential to correctly track the passage of the year by using a calendar.

The motion of the Sun

The earth goes around the sun once every 365.2425 days. This number is rather inconvenient as it can not be divided up into a whole number of days. To work out the day within the year you can measure the angle of the sun at midday, but this assumes you have an accurate idea of time. It is at its highest at the Summer Solstice ➚ on 21st/22nd June and lowest on the Winter Solstice 21st/22nd December [northern hemisphere]. Alternatively if you have some sort of clock you can measure when the length of a day is equal to the length of a night, and so identify the Spring and Autumn Equinoxes ➚. The earliest astronomical instrument is just a stick in the ground - a gnomon ➚ to measure the sun's shadow - from which the sundial is a direct descendent. Using the gnomon allows the solstices to be found based on the longest and shortest shadows.

In the western Julian Calendar ➚ an extra leap day needs to be inserted into the calendar every four years (4 x 0.25 = 1) to keep the solar calendar synchronized with the earth’s orbit. However, the number of days is actually a little less than 365.25 it is closer to 365.2425, to account for this discrepancy the Gregorian calendar ➚ was introduced with additional rules for leap days in century years (2100 will not be a leap year but 2000 was). By the time the Gregorian system was introduced in 1582, the old Julian calculation had drifted from the true solar time by ten days or more. There were mass protests when these days were wiped from existence. The Orthodox Eastern Church ➚ has still not accepted the Gregorian system and that is why they celebrate Easter ➚ on a much later date.

The Stars

Perhaps more useful than using the sun as a clock is to take a look up at the stars. [For more on Chinese constellations please visit: Chinese stars and constellations]. The sun appears to move relative to the backdrop of stars in an annual cycle - and so the constellation the sun is currently in front of tells you the approximate date. As the sun is so bright, this observation has to be made just before sunrise or after sunset. The stars appear to rotate about one point in the night star - the pole star. The Chinese used the pole star and circumpolar stars rather than the sun as these are easier to observe directly and accurately. As summer progresses different stars and constellations appear above the southern horizon ➚ and this is another way of working out the date.

The motion of the Moon

The moon has been the most useful clock for thousands of years. The moon takes 29.53 days to go around the earth and just as importantly the phase of the moon changes through this period from full to half to new to half and back to full again. By carefully tracking the phase of the moon you can work out the day within a month. It is best to work with the new moon as the starting day of the month, as it is easy to see when the disc is entirely dark without even a slither of light at its edge. People can then easily count through the days within the month up to 29, so as long as it is agreed when is the day of the new moon, you can agree dates and make arrangements for meetings on particular future days based on this lunar calendar.

The word ‘calendar’ comes from the Latin kalendae ➚ ‘to announce’ referring to the Roman custom of announcing the official new moon that started the month; everyone then started counting the days within the new month.

Most regrettably the date calculated by the sun is out of step to that by the moon. There are 12.37 lunar orbits in a year and coping with this awkward number was a real problem for human civilizations. If this was a whole number then calendars would be far simpler. It is likely that this incomplete thirteenth part month of the solar year is the true origin of 'unlucky thirteen ➚'.

One coincidence is that 19 x 12.37 is very close to the whole number of 235 (it's actually 235.03) and so the lunar and solar cycles roughly repeat each other every 19 years - this is called the Metonic cycle named after the Greek mathematician Meton ➚, who discovered it in 432BCE. The Chinese had independently discovered this as early as 600BCE.

Chinese Calendars

China has adopted the western Gregorian system of strange lengths of months with extra leap days at the end of February to correct for the true length of solar year. This was introduced into China when it became a Republic in 1912. New public holidays such as Labor Day (May 1st) and National Day (October 1st) are fixed on the Gregorian calendar.

China developed its traditional calendar system independently from the West. China has two calendars which are still followed today, one based on the moon and one on the sun.

The lunar Chinese calendar is the most important as it determines the dates of many Chinese traditional festivals. Instead of adding an extra leap day every four years the calendar introduces a whole leap month every few of years. This calendar follows the moon precisely so months are either 29 or 30 days long according to accurate predictions of the occurrence of the new moon at a specific place. The months are called 小月 xiǎo yuè small months (29) and 大月 dà yuè big months (30) and are numbered rather than named.

This may seem a little complicated until you bear in mind that some Christian festivals such as Easter are still synchronized to the moon and not the sun. Christians developed a similarly complex calculation to the Chinese for calculating the date for Easter ➚ each year.

Chinese Seasons

The start of the Chinese lunar year 年 nián is at the Spring Festival or Chinese New Year, timed as the second new moon after the Winter Solstice. The Chinese originally split the year into two seasons Spring 春 chūnand Autumn 秋 qiū (hence the name 'Spring and Autumn period'). These were split to form the four modern seasons by adding Summer 夏 xià and Winter 冬 dōng. However, for a brief time an extra season was added so that there were five seasons to tie in with five elements. The lunar months were named within the season so 孟春 mèng chūn was the first month of Spring; 中春 zhōng chūn the second month and 季春 jì chūn the last month of Spring.

An extra month

The position in the year that the Chinese leap (intercalary) month is added varies from year to year. In 2023 it will be added after the second month and in 2025 after the sixth month. The month is called after the normal month it follows with the addition of ‘leap’闰 rùn in the month's name. So the sequence in 2012 was 四月 sì yuè followed by 四闰月 sì rùn yuè. A year with a leap or double 8th month is considered a very unlucky year (1976, 1995, 2014 and 2033). The addition of a whole extra month yields a length of year that can vary from 353 to 385 days.

The invention of the lunar calendar is attributed to the Yellow Emperor back in the mists of ancient China. Very accurate astronomical measurements need to be taken to keep the lunar calendar in step with the complex orbit of the moon. For many centuries the Purple Mountain Astronomical Institute ➚ at Nanjing calculated the calendar for China.

Lunar dates

You will see some extra characters on Chinese calendars (including our own free calendar) : Days of the lunar month in the range 1 to 10 use the character prefix 初 chū for ‘early’. Instead of using three characters for 21 to 29 (二十一 èr shí yī and so on) a special character for ‘twenty’ 廿 niàn is used. The number 30 is represented as 三十 sān shí and there is no need for 31 as there are only ever 29 or 30 days in month. This convention gives all days a convenient two character form.

Lunar names

The months 2 to 10 are now numbered as you would expect but there is the special case of the first month which is called 正 zhēng. To keep to the same two character format as with days, the 11th month is sometimes called 冬 dōng (cold) and the 12th month is 腊 là (an alternative meaning is dried meat reflecting the lack of fresh meat in January).

Although lunar months are normally numbered they also have traditional poetic names.

Cycles of 60 and the counting of Years

Years are now counted just like ordinary numbers; the year of the Common Era. In Imperial China years were specified as the year number of the Emperor’s reign or, after 1911, from Yellow Emperor Huangdi's birth. The same scheme of regnal years ➚ was used in Europe up until recent times. By tradition a life span was at most 60 years, and so a special sexagesimal numbering system for years was also used for the Chinese astrological year. There is some evidence that in ancient days people who reached the age of sixty were buried alive in northern China as it was considered unnatural to live any longer than that. However in the 3rd century CE thinkers like Ji Kang ➚ correctly said that the longest achievable life span was 120 (2 x 60) years. The first years of the new cycle were considered the appropriate time to launch a revolution. Emperor Qianlong abdicated his rule after sixty years of reign in 1794 as he stated in his abdication proclamation that his cycle of rule had ended.

The sixty year cycle that has been used since the Han dynasty is made up of the Ten Heavenly Stems (天干 tiān gàn) combined with Twelve Earthly Branches (地支 dì zhī) that are also used for the astrological years.

The 12 year cycle of branches has its origin as far back as the Shang dynasty in the orbit of the planet of Jupiter. Early observations had shown Jupiter takes about 12 years to orbit the sun (11.86 is the actual figure), and the twelve branches was used to denote the years in the cycle. The earthly branches also denote a direction (see our astrology page) so compasses had 12 divisions not four or eight as in early Western systems. Another astronomical basis for the primacy of 60 is that there is a conjunction between the orbits of Saturn and Jupiter every 60 years (actually 59.58). For this reason Jupiter is sometimes known in China as the ‘year star’ 岁星 suì xīng.

In ancient times the Chinese split the year into six 60 day periods (double months) to make a 360 day year and so the historic importance of cycles of 60 can be clearly seen. It is interesting that the Mesopotamians ➚ used units of sixty for everything, from which we have ended up with 60 minute hours and 60 second minutes. In China there is a traditional epoch of 60x60x60x16x7 years making up 24,192,000 years.

The Ten Heavenly Stems 十天干 shí tiān gān

Each heavenly stem is associated with a number, an element and specific associations. Their principal use is as ‘ordinals’ from ancient time so the third day or the third year would both use the ordinal stem character 丙 bǐng. A week in Shang dynasty times (as recorded on oracle bones) was ten days long. Some legal documents today still use these characters for numbering.

No	Char	Pinyin	Element	Material
1	甲	jiǎ	Wood	Trees
2	乙	yǐ	Wood	Timber
3	丙	bǐng	Fire	Lightning
4	丁	dīng	Fire	Incense
5	戊	wù	Earth	Hills
6	己	jǐ	Earth	Pottery
7	庚	gēng	Metal	Ore
8	辛	xīn	Metal	Vessels
9	壬	rén	Water	Sea water
10	癸	guǐ	Water	Fresh water

The Twelve Earthly Branches 地支dìzhī

Each month is associated with an earthly branch. These also denote the astrological years, directions, months and times of day.

No	Char	Pinyin	Zodiac	Direction	Month	Time of day
1	子	zǐ	Rat 鼠	0° (north) winter	11	11pm to 1am (midnight)
2	丑	chǒu	Ox 牛	30°	12	1am to 3am
3	寅	yín	Tiger 虎	60° spring	1	3am to 5am
4	卯	mǎo	Rabbit 兎	90° (east)	2	5am to 7am
5	辰	chén	Dragon 竜	120°	3	7am to 9 am
6	巳	sì	Snake 蛇	150° summer	4	9am to 11am
7	午	wǔ	Horse 马	180° (south)	5	11am to 1pm (noon)
8	未	wèi	Goat 羊	210°	6	1pm to 3pm
9	申	shēn	Monkey 猿	240° autumn	7	3pm to 5pm
10	酉	yǒu	Rooster 鸡	270° (west)	8	5pm to 7pm
11	戌	xū	Dog 狗	300°	9	7pm to 9pm
12	亥	hài	Pig 猪	330° winter	10	9pm to 11pm

Sexagesimal Cycles干支 gānzhī

They are incremented in step to form a cycle of 60 so that:

1 : 甲子 1st stem and 1st branch is followed by 2: 乙丑 2nd stem and 2nd branch then 3: 丙寅 3rd stem and branch and so on up to 10: 癸酉 having run out of stems for 11 the stems start again at one but the stems continue at 11: 甲戌; 12: 乙亥, now at 13 the cycle of branches starts again 13:丙寅. The sequence does not repeat until 60 :癸亥 guǐhài. It may seem a cumbersome system, but it is less prone to misreading or mishearing as two characters together provide the number not just one. To record a year these two characters were combined with the Emperor's reign name. Here is the complete table of the 60 year names of the Sexagesimal Cycle.

The cycle of sixty was all important for recording times as it was not only used for counting the years but also day within the year and the time of day. Four gan zhi together give the exact time: year, month, day and time of day. You may still see this 8 character date and time format in some atrological readings.

1 甲子 jiǎ zǐ	13 丙子 bǐng zǐ	25 戊子 wù zǐ	37 庚子 gēng zǐ	49 壬子 rén zǐ
2 乙丑 yǐ chǒu	14 丁丑 dīng chǒu	26 己丑 jǐ chǒu	38 辛丑 xīn chǒu	50 癸丑 guǐ chǒu
3 丙寅 bǐng yín	15 戊寅 wù yín	27 庚寅 gēng yín	39 壬寅 rén yín	51 甲寅 jiǎ yín
4 丁卯 dīng mǎo	16 己卯 jǐ mǎo	28 辛卯 xīn mǎo	40 癸卯 guǐ mǎo	52 乙卯 yǐ mǎo
5 戊辰 wù chén	17 庚辰 gēng chén	29 壬辰 rén chén	41 甲辰 jiǎ chén	53 丙辰 bǐng chén
6 己巳 jǐ sì	18 辛巳 xīn sì	30 癸巳 guǐ sì	42 乙巳 yǐ sì	54 丁巳 dīng sì
7 庚午 gēng wǔ	19 壬午 rén wǔ	31 甲午 jiǎ wǔ	43 丙午 bǐng wǔ	55 戊午 wù wǔ
8 辛未 xīn wèi	20 癸未 guǐ wèi	32 乙未 yǐ wèi	44 丁未 dīng wèi	56 己未 jǐ wèi
9 壬申 rén shēn	21 甲申 jiǎ shēn	33 丙申 bǐng shēn	45 戊申 wù shēn	57 庚申 gēng shēn
10 癸酉 guǐ yǒu	22 乙酉 yǐ yǒu	34 丁酉 dīng yǒu	46 己酉 jǐ yǒu	58 辛酉 xīn yǒu
11 甲戌 jiǎ xū	23 丙戌 bǐng xū	35 戊戌 wù xū	47 庚戌 gēng xū	59 壬戌 rén xū
12 乙亥 yǐ hài	24 丁亥 dīng hài	36 己亥 jǐ hài	48 辛亥 xīn hài	60 癸亥 guǐ hài

At the birth of a Republic in 1912 there had to be a change to year numbers as there was no longer an Emperor. They chose to adopt the traditional count of years since the birth of the Yellow Emperor Huangdi. It is based on the 'lunar' year so the year number advances on the day of the Chinese New Year (Spring) festival. So February 1st 2022 is the start of Chinese year 4720. Sometimes the sexagesimal year is noted relative to this base year so 2022 is the 39th year of the 78th cycle since Huangdi. To find the Chinese year add 2698 to the Christian year, but take one off if the date precedes the Chinese New Year (Spring Festival).

For a full year's view please see our 2024 calendar and 2025 calendar.