Numbers and Time in Vietnamese

Overview

Vietnamese numbers follow a logical decimal system that is relatively straightforward once you learn the digits one through ten. Numbers combine predictably for teens, tens, and hundreds. Time-telling uses a question-and-answer pattern centered on "mấy giờ" (what time) and follows a 12-hour system in casual speech with morning/afternoon/evening indicators.

At the CEFR A1 level, numbers are essential for shopping, telling time, giving phone numbers, and discussing quantities. The number system is consistent with few irregularities, making it one of the more learner-friendly aspects of Vietnamese.

Vietnamese currency (đồng) involves very large numbers in everyday transactions, so comfort with numbers in the thousands and millions is practical from the very beginning of your studies.

How It Works

Basic numbers (0-10):

Number	Vietnamese
0	không
1	một
2	hai
3	ba
4	bốn
5	năm
6	sáu
7	bảy
8	tám
9	chín
10	mười

Teens and tens:

Number	Vietnamese	Pattern
11	mười một	10 + 1
15	mười lăm	10 + 5 (năm becomes lăm)
20	hai mươi	2 × 10
21	hai mươi mốt	2 × 10 + 1 (một becomes mốt)
25	hai mươi lăm	2 × 10 + 5 (lăm)
100	một trăm
1,000	một nghìn/ngàn	nghìn (N) / ngàn (S)

Telling time:

Vietnamese	English
Mấy giờ rồi?	What time is it?
Ba giờ.	3 o'clock.
Ba giờ rưỡi.	3:30 (half past 3).
Ba giờ mười lăm (phút).	3:15.
Sáng/trưa/chiều/tối	morning/noon/afternoon/evening

Examples in Context

Vietnamese	English	Note
một hai ba bốn năm	1, 2, 3, 4, 5	basic counting
Bây giờ mấy giờ?	What time is it now?	time question
ba giờ chiều	3 PM	time of day indicator
bao nhiêu tiền?	How much (money)?	price question
hai mươi nghìn đồng	20,000 dong	currency
Tôi mười tám tuổi.	I am 18 years old.	age expression
số điện thoại	phone number	number context
một trăm hai mươi ba	123	compound number
nửa giờ	half an hour	duration
năm phút	five minutes	duration

Common Mistakes

Forgetting Lăm and Mốt Variants

• Wrong: hai mươi năm for 25
• Right: hai mươi lăm (năm becomes lăm in tens position)
• Why: Vietnamese has special forms for 1 and 5 when they appear in the ones position of numbers above 10.

Confusing Mấy and Bao Nhiêu

• Wrong: Using "bao nhiêu" for small expected numbers
• Right: Use "mấy" for small numbers (under ~10), "bao nhiêu" for larger/unknown quantities
• Why: "Mấy" implies a small expected answer; "bao nhiêu" is open-ended.

Omitting Time-of-Day Indicators

• Wrong: Ba giờ without context (3 o'clock -- AM or PM?)
• Right: Ba giờ chiều (3 PM) or ba giờ sáng (3 AM)
• Why: Vietnamese typically uses 12-hour time with sáng/chiều/tối to disambiguate.

Usage Notes

In everyday transactions, prices in Vietnamese đồng are often quoted in shortened forms: "hai mươi" (twenty) means 20,000 đồng, with the thousands implied. This takes practice to get used to. Northern Vietnamese uses "nghìn" for thousand while Southern uses "ngàn."

Practice Tips

• Practice counting to 100 daily until the mươi/mười pattern and the lăm/mốt variants become automatic.
• Use real-world practice: read prices on menus, practice saying phone numbers digit by digit, and tell the time in Vietnamese whenever you check a clock.

Related Concepts

• Prerequisite: Classifiers — numbers require classifiers before nouns
• Next steps: Basic Time Words — time expressions beyond clock time
• Next steps: Days, Months, and Dates — calendar vocabulary