Vietnamese numbers are refreshingly logical. Learn ten words, a handful of combination rules, and you can count to a million. The hard part isn't memory, it's the tones: năm with the wrong tone stops meaning "five." This guide gives you the full system, the three irregularities that trip up every learner, and how to survive prices in a currency where a coffee costs 30,000.
These ten words are the foundation of everything else.
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| Number | Vietnamese | Pronunciation |
|---|---|---|
| 0 | không | kohng (flat, level tone) |
| 1 | một | moht (short, low, cut off sharply) |
| 2 | hai | high (flat) |
| 3 | ba | bah (flat) |
| 4 | bốn | bohn (rising) |
| 5 | năm | num (flat) |
| 6 | sáu | sow (rising) |
| 7 | bảy | bye (dipping then rising) |
| 8 | tám | tahm (rising) |
| 9 | chín | cheen (rising) |
| 10 | mười | muh-uh-ee (falling) |
Two pairs deserve extra drilling because learners mix them up constantly: bốn (4) vs bảy (7), and năm (5) vs lăm (the form of 5 you'll meet below). And note that một (1) ends with a hard stop, almost swallowed. Reading romanized approximations only gets you so far here; tones live in your ears, not on the page. Listen to native audio and repeat out loud until each number feels automatic.
Add the digit after mười (10). One irregularity: 15 is mười lăm, not mười năm. The word năm also means "year," so Vietnamese swaps it for lăm after tens to avoid ambiguity.
| Number | Vietnamese |
|---|---|
| 11 | mười một |
| 12 | mười hai |
| 13 | mười ba |
| 14 | mười bốn |
| 15 | mười lăm |
| 16 | mười sáu |
| 17 | mười bảy |
| 18 | mười tám |
| 19 | mười chín |
From 20 upward, the pattern flips: digit first, then mươi (note the tone change from mười to mươi, falling to flat).
| Number | Vietnamese |
|---|---|
| 20 | hai mươi |
| 30 | ba mươi |
| 40 | bốn mươi |
| 50 | năm mươi |
| 60 | sáu mươi |
| 70 | bảy mươi |
| 80 | tám mươi |
| 90 | chín mươi |
Compound numbers like 21-99 follow tens + unit, but three digits change form:
1 becomes mốt after any ten from 20 up. 21 is hai mươi mốt, 31 is ba mươi mốt, 91 is chín mươi mốt. Never hai mươi một.
5 becomes lăm after any ten. 25 is hai mươi lăm, 35 is ba mươi lăm, 55 is năm mươi lăm. This is the same rule you saw in 15.
4 often becomes tư after tens. 24 can be hai mươi tư or hai mươi bốn; both are understood, but tư is very common in speech, especially in the south. Recognize both.
| Number | Vietnamese | Rule |
|---|---|---|
| 21 | hai mươi mốt | một → mốt |
| 24 | hai mươi tư (or bốn) | bốn → tư |
| 25 | hai mươi lăm | năm → lăm |
| 44 | bốn mươi tư | |
| 55 | năm mươi lăm | |
| 99 | chín mươi chín | regular |
In fast casual speech you'll also hear mươi dropped entirely: hai mốt (21), ba lăm (35). Don't imitate this at first, but expect it at markets.
| Number | Vietnamese |
|---|---|
| 100 | một trăm |
| 200 | hai trăm |
| 1,000 | một nghìn (north) / một ngàn (south) |
| 10,000 | mười nghìn |
| 100,000 | một trăm nghìn |
| 1,000,000 | một triệu |
To build any number, stack from largest to smallest: 345 = ba trăm bốn mươi lăm. 1,999 = một nghìn chín trăm chín mươi chín.
One extra rule: when a hundred is followed directly by units with no tens (like 105), insert lẻ (south) or linh (north): 105 = một trăm lẻ năm. Skipping it sounds wrong to native ears.
Vietnam's currency, the đồng (VND), comes in big numbers: at roughly 25,000 VND to the dollar, everyday prices land between 10,000 and a few hundred thousand. So price talk is really thousands talk:
Vendors shorten aggressively. Nghìn gets dropped ("ba mươi" for 30,000), and you'll hear chục (a colloquial "ten") in phrases like năm chục for 50,000. If a market price sounds impossibly small, mentally re-attach the thousands.
Two survival phrases: Bao nhiêu tiền? (How much?) and Đắt quá! (Too expensive!).
Reading a table once won't survive contact with a real market. Two things work:
Shadowing for the tones. Play native audio of each number, repeat immediately, matching pitch, not just the sounds. Tones are motor skills; your mouth learns them by copying, not by studying tone diagrams. This is exactly how Hyperpolyglot's reader works: native audio on every phrase, tap to replay, repeat until it sticks.
Spaced repetition for retention. Numbers are ideal SRS material: small, discrete, unambiguous. Drill 1-10 first, then the irregular forms (mốt, lăm, tư) as separate cards, then random prices like bảy mươi lăm nghìn. A few minutes daily beats one long session, and an app that schedules reviews for you removes the willpower tax. Hyperpolyglot combines both, native audio plus built-in spaced repetition, on iOS, Android, and Web.
Then use them. Count your reps at the gym in Vietnamese. Read prices out loud. Numbers come up in every single conversation, which means every conversation is free review.
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