# Vì vậy / vì thế: therefore in Vietnamese (B1)

> Vì vậy means "that's why" or "therefore". It starts the result, after you've given the reason: Tuần này em bận lắm, vì vậy em không đi được.

Source: https://vietnamesebuddy.com/grammar/vi-vay-therefore/ · Updated 2026-10-17

**therefore**

Pattern: `[sentence]. Vì vậy / Vì thế, [sentence]`

Level: B1 (our estimate) · Register: everyday

Typed without accents: vi vay, vi the

Situations: [At work](https://vietnamesebuddy.com/grammar/?use=work)

Variants:

- do đó (written)
- vậy nên (speech)
- bởi vậy
- thành ra
- thành thử

*Vì vậy* means "that's why" or "therefore". It starts the result, after you've given the reason: *Tuần này em bận lắm, vì vậy em không đi được.* I'm really busy this week, so I can't go. *Vì thế* means the same; Saigon leans to *vì vậy*, Hà Nội to *vì thế*.

It's *vì* (because) plus *vậy* (that): "because of that". So it always comes after the reason, at the start of the result, often after a full stop or a comma: *Giá xăng tăng. Vì vậy, giá đồ ăn cũng tăng.* Petrol went up. That's why food prices went up too.

You know *nên* (so), which joins the two halves into one quick sentence: *Em bận nên em không đi được.* That's the most common choice in conversation. *Vì vậy* puts a small pause between reason and result, so it suits explaining, at work and in writing. In notices, reports and the news you'll also see *do đó*. In relaxed Saigon speech, *vậy nên* and *thành ra* do the same job.

*Vậy là* is different: it tells what happened next in a story. *Vì vậy* gives the reason.

## Examples

- Tuần này em bận lắm, vì vậy em không đi được. — I'm really busy this week, so I can't go.
- Giá xăng tăng, vì vậy giá đồ ăn cũng tăng. — Petrol prices went up, so food prices went up too.
- Anh ấy làm việc chăm chỉ, vì thế được tăng lương. — He works hard; that's why he got a raise.
- Đường đang sửa, do đó xe buýt phải đi đường khác. — The road is under repair, so buses have to take another route.

## Words in this pattern

- [vì vậy](https://vietnamesebuddy.com/words/vi-vay/#s_vi_vay): therefore

## Compare

- [Because …, so …: vì … nên](https://vietnamesebuddy.com/grammar/vi-nen-so/): because …, so
- [And so, so then: vậy là / thế là](https://vietnamesebuddy.com/grammar/the-la-so-then/): and so (it happened)

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