For official information and on radio, television and newspapers, the 24-hour system is used by the hour together with the word นาฬิกา นาฬิกา [na:-- li/ ga:--] = Clock.

Example: ยี่สิบนาฬิกา [ji:/\ sip\ na:-- li/ ga:-- ]means 20:00 o'clock = 8 pm.

On the other hand, in everyday conversation among Thais, the traditional system is used.

Basis for this system is to divide the day into several time periods, like morning, afternoon or evening. But the Thai system has other, partly overlapping subdivisions:

In any particular period the hours will be counted for this period starting from one: 13:00 o'clock is the first afternoon hour and is named บ่ายหนึ่งโมง (for the first hour หนึ่ง can be omitted = บ่ายโมง). 14:00 o'clock therefore is named บ่ายสองโมง = afternoon, second hour.

From 19:00 to 23:00 o'clock (ตอนค่ำ) ทุ่ม is used: 20:00 o'clock, the second hour of the evening is สองทุ่ม.

In the morning there is a difference in so far that they begin at 6:00 clock in the morning with หกโมงเช้า and are counted up to 11:00 clock สิบเอ็ดโมงเช้า. But the traditional system in which the hours are counted starting with one, is also common. However 6:00 o'clock in the morning is always หกโมงเช้า, the first morning hour 7:00 o'clock starts counting with one หนึ่งโมงเช้า or simple โมงเช้า, going on up to the fifth morning hour ห้าโมงเช้า = 11:00 o'clock.

The whole traditional system is shown the following graphic:

When referring to the odd times the hourly fractions are added to the full hour. ครึ่ง = "half" can be used, all other hourly fractions are given in minutes: