| Date and time notation in Thailand | |
| Label1: | Full date |
| Label2: | All-numeric date |
| Label3: | Time |
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 (๑ มิถุนายน พ.ศ. ๒๕๖๘ or 1 มิถุนายน พ.ศ. 2568). While a 24-hour system is common for official use, colloquially, a 12-hour format with terms like "morning" (th|เช้า;) and "night" (ค่ำ, kham), etc., or a modified six-hour format is used.
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.[1] 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 "พ.ศ." (Buddhist Era) or "ค.ศ." (Anno Domini) to avoid confusion. As each calendar is 543 years apart, there is very little confusion in the contemporary context.
Day in a week(Thai : สัปดาห์, pronounced [S̄ạpdāh̄̒]) 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 | Thai | RTGS | ||
|---|---|---|---|---|
| Sunday | วันอาทิตย์ | Wan Athit | อา. | |
| Monday | วันจันทร์ | Wan Chan | จ. | |
| Tuesday | วันอังคาร | Wan Angkhan | อ. | |
| Wednesday | วันพุธ | Wan Phut | พ. | |
| Thursday | วันพฤหัสบดี | Wan Phruehatsabodi or Pharuehatsabodi | พฤ. | |
| Friday | วันศุกร์ | Wan Suk | ศ. | |
| Saturday | วันเสาร์ | Wan Sao | ส. |
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 -yon (-ยน), while those with 31 days end with -khom (-คม). An exception is February, which is designated with the suffix -phan (-พันธ์) 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 pi athikasuratin (ปีอธิกสุรทิน).
| English | Thai | RTGS | |||
|---|---|---|---|---|---|
| 1 | January | มกราคม | Makarakhom or Mokkarakhom | ม.ค. | |
| 2 | February | กุมภาพันธ์ | Kumphaphan | ก.พ. | |
| 3 | March | มีนาคม | Minakhom | มี.ค. | |
| 4 | April | เมษายน | Mesayon | เม.ย. | |
| 5 | May | พฤษภาคม | Pruetsaphakhom | พ.ค. | |
| 6 | June | มิถุนายน | Mithunayon | มิ.ย. | |
| 7 | July | กรกฎาคม | Karakadakhom or Karakkadakhom | ก.ค. | |
| 8 | August | สิงหาคม | Singhakhom | ส.ค. | |
| 9 | September | กันยายน | Kanyayon | ก.ย. | |
| 10 | October | ตุลาคม | Tulakhon | ต.ค. | |
| 11 | November | พฤศจิกายน | Phruetsachikayon | พ.ย. | |
| 12 | December | ธันวาคม | Thanwakhom | ธ.ค. |
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.
The lunar calendar (th|ปฏิทินจันทรคติ;) 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 (ข้างขึ้น; khang khuen) and the waning moon (ข้างแรม; khang raem).
The traditional Thai lunar calendar follows the Buddhist Era (พุทธศักราช; phutthasakkarat), which is 543 years ahead of the Gregorian calendar.
Important dates on the Thai calendar were often connected to Buddhism, such as Vesakha Puja (วันวิสาขบูชา; wan wisakhabucha), which commemorates the birth, enlightenment, and passing of the Buddha. These holidays are determined by the lunar calendar.
Shaka era[2] (th|มหาศักราช;) 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[3] (th|จุลศักราช;) 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.
The Ratanakosin Era[4] (RS, th|รัตนโกสินทร์ศก,) 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.
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.
See main article: Thai numerals. 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, ๑ มิถุนายน พ.ศ. ๒๕๕๖.[5]
| 0 | ๐ | sun | ศูนย์ | |
| 1 | ๑ | nueng | หนึ่ง | |
| 2 | ๒ | song | สอง | |
| 3 | ๓ | sam | สาม | |
| 4 | ๔ | si | สี่ | |
| 5 | ๕ | ha | ห้า | |
| 6 | ๖ | hok | หก | |
| 7 | ๗ | chet | เจ็ด | |
| 8 | ๘ | paet | แปด | |
| 9 | ๙ | kao | เก้า | |
| 10 | ๑๐ | sip | สิบ |
The time points of days in the past, present, and future, which are found in the Thai language, are expressed using various words, including:[6]
The time points of months in the past, present and future, which are found in Thai language, are expressed using many words, including:
The time points of years in the past, present and future, which are found in Thai language, are expressed using many words, including:
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.[7] 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:[8]
Thailand is in the time zone, which is also known as Indochina Time (ICT) and military time zone Golf.
See main article: 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:[9]
The terms mong and thum 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. mong represents the sound of the gong, associated with signaling the day, while thum represents the sound of the drum, used to signify the night. This system of timekeeping was formalized during the reign of King Mongkut.
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 "นาฬิกา" [10]
| 24-hour numerical notation | Time | Modified 6-hour | 24-hour | |||
|---|---|---|---|---|---|---|
| Thai | RTGS | Thai | RTGS | |||
| 24:00 or 00:00 | Midnight | เที่ยงคืน | thiang khuen | ยี่สิบสี่นาฬิกา or ศูนย์นาฬิกา | yi-sip-si nalika or sun nalika | |
| 01:00 | 1 early morning | ตีหนึ่ง | ti nueng | หนึ่งนาฬิกา | nueng nalika | |
| 02:00 | 2 early morning | ตีสอง | ti song | สองนาฬิกา | song nalika | |
| 03:00 | 3 early morning | ตีสาม | ti sam | สามนาฬิกา | sam nalika | |
| 04:00 | 4 early morning | ตีสี่ | ti si | สี่นาฬิกา | si nalika | |
| 05:00 | 5 early morning | ตีห้า | ti ha | ห้านาฬิกา | ha nalika | |
| 06:00 | 6 in the morning | หกโมงเช้า | hok mong chao | หกนาฬิกา | hok nalika | |
| 07:00 | 7 in the morning | เจ็ดโมงเช้า | chet mong chao | เจ็ดนาฬิกา | chet nalika | |
| 08:00 | 8 in the morning | แปดโมงเช้า | paet mong chao | แปด นาฬิกา | paet nalika | |
| 09:00 | 9 in the morning | เก้าโมงเช้า | kao mong chao | เก้านาฬิกา | kao nalika | |
| 10.00 | 10 in the morning | สิบโมงเช้า | sip mong chao | สิบ นาฬิกา | sip nalika | |
| 11.00 | 11 in the morning | สิบเอ็ดโมงเช้า | sip-et mong chao | สิบเอ็ด นาฬิกา | sip-et nalika | |
| 12:00 | Midday | เที่ยงวัน | thiang wan | สิบสองนาฬิกา | sip-song nalika | |
| 13:00 | 1 in the afternoon | บ่ายโมง | bai mong | สิบสามนาฬิกา | sip-sam nalika | |
| 14:00 | 2 in the afternoon | บ่ายสองโมง | bai song mong | สิบสี่นาฬิกา | sip-si nalika | |
| 15:00 | 3 in the afternoon | บ่ายสามโมง | bai sam mong | สิบห้านาฬิกา | sip-ha nalika | |
| 16:00 | 4 in the afternoon | บ่ายสี่โมง | bai si mong | สิบหกนาฬิกา | sip-hok nalika | |
| 17:00 | 5 in the afternoon | ห้าโมงเย็น | ha mong yen | สิบเจ็ดนาฬิกา | sip-chet nalika | |
| 18:00 | 6 in the evening | หกโมงเย็น | hok mong yen | สิบแปดนาฬิกา | sip-paet nalika | |
| 19:00 | 1 at night | หนึ่งทุ่ม | nueng thum | สิบเก้านาฬิกา | sip-kao nalika | |
| 20:00 | 2 at night | สองทุ่ม | song thum | ยี่สิบนาฬิกา | yi-sip nalika | |
| 21:00 | 3 at night | สามทุ่ม | sam thum | ยี่สิบเอ็ดนาฬิกา | yi-sip-et nalika | |
| 22:00 | 4 at night | สี่ทุ่ม | si thum | ยี่สิบสองนาฬิกา | yi-sip-song nalika | |
| 23:00 | 5 at night | ห้าทุ่ม | ha thum | ยี่สิบสามนาฬิกา | yi-sip-sam nalika | |