Telling the time: giờ, rưỡi, kém

For the hour, say the number and then giờ (o'clock): bảy giờ, seven o'clock. For minutes, add the number after it: bảy giờ mười lăm, 7:15. You can add phút (minutes), but in speech it's often left off, except usually for one to nine minutes: mười giờ năm phút, 10:05. Half past is rưỡi: bảy giờ rưỡi. "Sharp" is đúng: đúng bảy giờ.

For the minutes before the hour, use kém (short of): tám giờ kém mười is ten to eight, literally "eight o'clock short ten". The hour comes first, the opposite of English. You'll sometimes hear thiếu instead of kém in the South, and many Saigon speakers simply count the minutes up: bảy giờ năm mươi.

To ask the time, say Mấy giờ rồi? The rồi means "by now", and the answer usually keeps it: Chín giờ rưỡi rồi. It's half past nine. To say "at" a time, put lúc before it: Xe buýt chạy lúc tám giờ. The bus leaves at eight. To ask when, use (lúc) mấy giờ: Mấy giờ xe chạy?

For morning or evening, add sáng, chiều or tối at the end: bảy giờ tối. Timetables use the 24-hour clock, often written 19h30. For a length of time in hours, people usually say tiếng: hai tiếng, two hours. Hai giờ alone sounds like two o'clock; if you use giờ, say hai giờ đồng hồ.