# Noun + mấy in Vietnamese (A1)

> Put mấy after a noun and it asks which number, not how many: lầu mấy? (which floor?), lớp mấy? (which year at school?), phòng số mấy? (which room…

Source: https://vietnamesebuddy.com/grammar/may-which-number/ · Updated 2026-11-10

**which number (date, day, floor)?**

Pattern: `[noun] + mấy? · [noun] + (là) + bao nhiêu? (a phone number; a year takes either)`

Level: A1 (our estimate) · Register: everyday

Typed without accents: may

Put *mấy* after a noun and it asks which number, not how many: *lầu mấy?* (which floor?), *lớp mấy?* (which year at school?), *phòng số mấy?* (which room number?). The answer puts the number in the same place: *Lầu ba.*

Dates work this way too: *thứ mấy?* (which day of the week), *ngày mấy?* (which date), *tháng mấy?* (which month). *Thứ mấy* and *tháng mấy* take *mấy*. For the date, Saigon says *ngày mấy*; *ngày bao nhiêu* is also common, especially in Hà Nội. Days of the week are numbered from *thứ hai* (Monday) to *thứ bảy* (Saturday), but Wednesday is *thứ tư*, not *thứ bốn* (and April is *tháng tư*). Sunday is the odd one out: *chủ nhật*.

For a phone number, *bao nhiêu* is the usual choice: *Số điện thoại của chị là bao nhiêu?* For a birth year, both are heard, and *năm mấy* is very common in casual talk: *Em sinh năm mấy?*

Order matters. Before the noun, *mấy* asks how many: *mấy lầu* is how many floors, *lầu mấy* is which floor.

Floors differ by region. In Saigon a floor is *lầu* and the ground floor is *tầng trệt*, so *lầu một* is one floor up. In Hà Nội a floor is *tầng*, and *tầng một* is the ground floor.

## A common mistake

✗ Chị ở mấy lầu?

✓ Chị ở lầu mấy?

Before the noun, *mấy* asks how many: *mấy lầu*, how many floors. For which floor, *mấy* goes after: *lầu mấy*.

## Examples

- Hôm nay thứ mấy? — What day is it today?
- Hôm nay thứ sáu. — It's Friday.
- Saigon: Văn phòng anh ở lầu mấy? | Hà Nội: Văn phòng anh ở tầng mấy? — Which floor is your office on?
- Số điện thoại của chị là bao nhiêu? — What's your phone number?
- Em sinh năm mấy? — What year were you born?

## Compare

- [How many (a small number): mấy before the noun](https://vietnamesebuddy.com/grammar/may-how-many/): how many (few)?

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