Thailand has adopted ISO 8601 under national standard: TIS 1111:2535 in 1992. However, Thai date and time notation reflects the country’s cultural development through the years used. The formal date format is D/M/YYYY format (1/6/2568), nowadays using the Buddhist Era (BE). The full date format is day-month-year format which is written in Thai ( or ). While a 24-hour system is common for official use, colloquially, a 12-hour format with terms like "morning" (, ) and "night" (), etc., or a modified six-hour format is used.

Date Thailand uses the Thai solar calendar as the official calendar, in which the calendar's epochal date (Year zero) was the year in which the Buddha attained parinibbāna. This places the current year at 543 years ahead of the Gregorian calendar. The year AD is indicated as BE in Thailand. Despite adopting ISO 8601, Thai official date is still written in D/M/YYYY formats, such as 30 January 2567 BE (2024 AD) or 30/1/2567. Anno Domini may be used in unofficial context, and is written in the same format (D/M/YYYY).

In full date format, the year is marked with "" (Buddhist Era) or "" (Anno Domini) to avoid confusion. As each calendar is 543 years apart, there is very little confusion in the contemporary context.

Day in thai Day in a week (, ) according to the ISO 8601 international standard, Monday is designated as the first day of the week, while Sunday is considered as the last day. Meanwhile, in Thailand, Sunday was considered the start of the week, which ended on Saturday. English ThaiTransliteration (RTGS)SundayMondayTuesdayWednesdayThursday or FridaySaturday

Month in thai In Thai, the names of months can be categorized based on the number of days they contain. Months with 30 days typically end with the suffix (), while those with 31 days end with (). An exception is February, which is designated with the suffix () and has either 28 or 29 days depending on whether it is a leap year, as determined by the solar leap year system, referred to as (). EnglishThaiTransliteration (RTGS)1January or 2February3March4April5May6June7July or 8August9September10October11November12December

Year in thai The Thai calendar has evolved significantly throughout the nation's history, from their culture and tradition. Each era has been used to mark the passage of time, reflecting the historical and religious influences of the era.

Buddhist Era The lunar calendar (, ) system is based on the cycles of the moon. A lunar month lasts about 291/2 days, and the year consists of 12 months with the occasional insertion of an extra month (13th month) to keep the lunar and solar years aligned. Each month is divided into two phases the waxing moon () and the waning moon ().

The traditional Thai lunar calendar follows the Buddhist Era (), which is 543 years ahead of the Gregorian calendar.

Important dates on the Thai calendar were often connected to Buddhism, such as Vesakha Puja (), which commemorates the birth, enlightenment, and passing of the Buddha. These holidays are determined by the lunar calendar.

Shaka era Shaka era (, ) is widely used in historical evidence such as stone inscriptions and chronicles from both the Sukhothai and early Ayutthaya periods. Shaka era was established by King Kanishka of the Kushan dynasty, beginning after the Buddhist Era 622 (Shaka era corresponds to 622 CE).

Chula Sakarat Chula Sakarat (, ) is an era influenced by Burma. The king of Pagan first started using it in Burma in 1182 CE and it spread to the Lan Na Kingdom starting after 1181 CE. Thais like to use Chula Sakarat in astrological calculations and to indicate the year in inscriptions, legends, records, and chronicles until the time of King Chulalongkorn when he announced its abolition and used Rattanakosin Era instead.

Rattanakosin Era The Ratanakosin Era (RS, , ) was established on 1 April 1889 by Chulalongkorn, starting with the year Bangkok was declared as the capital as 1 RS. Thailand continued the Rattanakosin Era until 131 RS. It was announced to be canceled during the early reign of King Vajiravudh, eventually being turned into the Buddhist Era instead.

Gregorian year The Buddhist calendar is widely used in Southeast Asian countries that follow the Theravada school of Buddhism, particularly in Thailand, Cambodia, Laos, Myanmar, and Sri Lanka. In Thailand, it was formally adopted in 2455 BE (1912 AD), during the reign of Vajiravudh, replacing the Rattanakosin Era. Although it has been in use since the Ayutthaya period, it continues to be used today. The Buddhist Era (BE) starts one year after the Buddha's parinirvana, making the Buddhist calendar 543 years ahead of the Gregorian calendar.

Year calculation

Buddhist Era = Anno Domini + 543 Buddhist Era = Maha Sakarat + 621 Buddhist Era = Chula Sakarat + 1181 Buddhist Era = Rattanakosin Era + 2324

Thai numerals in Thai official document

Thai numerals are commonly used in official government documents in Thailand for conserving Thai cultures and it is in a day month year format by day and year are written in Thai numerals and month is written in Thai. Additionally, in the official documents, year is written in the Buddhist era. For example, to write a full date format, 1 June 2013, in Thai government documents, . +ArabicThai numeralsTransliteration (RTGS)Thai012345678910

Colloquialism in Thailand

Date colloquialism in Thailand The time points of days in the past, present, and future, which are found in the Thai language, are expressed using various words, including:

Past: "" () refers to yesterday or one day before today. "" () refers to the day before yesterday or two days before today. Present: "" () refers to today. Future: "" () refers to tomorrow or one day after today. "" () refers to the day after tomorrow or two days after today. "" () refers to three days after today.

Month colloquialism The time points of months in the past, present and future, which are found in Thai language, are expressed using many words, including:

Past: "" () refers to previous month or last month. "" () refers to previous month or last month. "" () refers to previous month or last month. "" () refers to a month that came before the last month but does not specify an exact time frame. Present: "" () refers to this month. Future: "" () refers to next month or one month after the current month. "" () refers to next month or one month after the current month. "" () or "" () refers to the month two months from now, two months after the current month or more.

Year colloquialism The time points of years in the past, present and future, which are found in Thai language, are expressed using many words, including:

Past: "" () refers to the year before last or one year before the current year. "" () refers to the year before last or one year before the current year. "" () refers to more than one year before the current year, but it does not specify exactly how many years ago. Present: "" () refers to this year. Future: "" () refers to next year or one year after the current year. "" () refers to next year or one year after the current year.

Time There are two systems of telling time in Thailand. Official time follows a 24-hour clock. The 24-hour clock is commonly used in military, aviation, navigation, meteorology, astronomy, computing, logistical, emergency services, and hospital settings, where the ambiguities of the 12-hour clock cannot be tolerated.

In the second, everyday usage, the day is divided into four six-hour periods. Additional words are used to identify the period specified (similar to a.m. or p.m. for a 12-hour system).

The distinguishing words are: 00:00-00:59 = () 01:00-05:59 = () 06:00-11:59 = () 12:00-12:59 = () 13:00-15:59 = () 16:00-18:59 = () 19:00-23:59 = ()

Thailand is in the UTC+07:00 time zone, which is also known as Indochina Time (ICT) and military time zone Golf.

Thai six-hour clock

The Thai six-hour clock divides the day into four distinct 6-hour periods and reflects traditional Thai customs. While modern Thailand primarily uses the 24-hour clock for official purposes, this system remains a cultural heritage from earlier Thai norms. It is still occasionally used in informal settings, especially in rural areas and casual conversation.

Notation of the Thai time system:

The first six-hour period (01:00–06:00) is expressed using the numbers 1 through 6, followed by the phrase "" (). The second six-hour period (07:00–12:59) is expressed using the numbers 1 through 6, followed by the phrase "" (). The third six-hour period (13:00–18:59) is expressed using the numbers 1 through 6, followed by the phrase "" () or "" (). The fourth six-hour period (19:00–00:59) is expressed using the numbers 1 through 6, followed by the phrase "" ().

The terms and originate from the sounds produced by traditional Thai instruments: the gong and the drum, respectively. These sounds were historically used as signals to mark the passage of time. represents the sound of the gong, associated with signaling the day, while represents the sound of the drum, used to signify the night. This system of timekeeping was formalized during the reign of King Mongkut.

Thai 24-hour clock The 24-hour clock in Thai is used similarly to the international system, especially in formal contexts like transportation, news, military, and government. By expressing 00:00-23:59, followed by the phase "" ()

24-hour numerical notation Time Modified 6-hour 24-hourThaiRTGSThaiRTGS24:00 or 00:00Midnight or or 01:001 early morning02:002 early morning03:003 early morning04:004 early morning05:005 early morning06:006 in the morning07:007 in the morning08:008 in the morning09:009 in the morning10.0010 in the morning11.0011 in the morning12:00Midday13:001 in the afternoon14:002 in the afternoon 15:003 in the afternoon 16:004 in the afternoon17:005 in the afternoon18:006 in the evening19:001 at night20:002 at night21:003 at night22:004 at night23:005 at night

See also Thai calendar Thai lunar calendar Thai solar calendar Thai six-hour clock

References