When do I use 用 vs 以?

Use 用 for everyday spoken and informal written Chinese when indicating a tool, method, or material. Use 以 only in formal or literary writing, especially in fixed patterns like 以…为… or to express purpose/reason.

Can I replace 以 with 用 in formal writing?

Not always. In formulaic expressions like 以政府名义 (in the name of the government) or 以资鼓励 (as encouragement), 以 is fixed. In other cases, 用 may be acceptable but would shift the register to less formal.

No, in modern standard Chinese 以 is a prepositional coverb. It is not used as an independent verb (unlike 用, which is also a verb). Its appearance in 以…为… is a set structure meaning 'take/use … as …'.

How do I negate 用 and 以 as coverbs?

用 can be negated: 不用 (bùyòng, 'not using / need not') and 没用 (méiyòng, 'useless / not used'). 以 is rarely negated as a coverb in modern Chinese; negation occurs only in classical or set phrases (e.g., 不以此故).

Easily confusedHSK 5

用 vs 以 (yòng vs yǐ): which “with” to use

Both 用 and 以 can indicate the means or instrument for an action. 用 is the standard everyday spoken word for 'with' (a tool, method, or material). 以 is a formal, literary coverb used mainly in written Chinese and fixed expressions like 以...为..., and can also introduce a purpose or reason. Choose 用 in conversation and informal writing; reserve 以 for formal or classical-styled texts.

In Chinese, both 用 and 以 serve as instrumental coverbs meaning 'with' or 'by means of', but they differ sharply in register and usage. 用 is the default choice in spoken and informal written Chinese, used for everyday tools, methods, materials, or languages. 以 is restricted to formal, literary contexts, often appearing in fixed structures such as 以...为... and idiomatic expressions; it can also purpose or reason ('in order to'). Understanding this register split is key to choosing the appropriate term.

When to use each

用yòng

with (means/instrument)

Use 用 in everyday speech and informal writing to indicate the tool, method, or material by which an action is performed. It functions as both a verb ('to use') and a coverb ('with'). Examples: 用筷子吃饭 (eat with chopsticks), 用中文说话 (speak in Chinese).

用 can be negated as 不用 (bùyòng, 'need not / not using') or 没用 (méiyòng, 'useless'), but note that 不用 in coverb position means 'not using' or 'no need to', not 'without'.

以yǐ

by means of (formal)

Use 以 in formal, written Chinese — such as documents, speeches, academic texts — to introduce the means or method. It often appears in fixed structures like 以...为... (take A as B), or combined with single‑character verbs (e.g., 以此, 以便). It can also express purpose or reason ('in order to').

以 is rarely used in spoken language; using it in casual conversation sounds stilted. It frequently appears in idiomatic expressions and formal contexts, and is seldom negated as a coverb.

At a glance

	用	以
Register	Informal / spoken / everyday writing	Formal / literary / official writing
Common structures	用 + noun + verb (用筷子吃)	以 + noun + verb (以此解决); often embedded in 以…为…
Meaning scope	Only means/instrument	Means/instrument AND purpose/reason (以…为目的, 以便)
Negation as coverb	可以: 不用, 没用 (rare in coverb use)	一般不用否定 (不以其道 is classical, not modern spoken)
Verb usage	Can be a full verb: 用钱 ('use money')	Not used as a standalone verb; only in 以…为… constructions

Examples

用
他用铅笔写字。
Tā yòng qiānbǐ xiě zì.
He writes with a pencil.
Everyday tool; 用 is natural here.
以
以此方式解决问题。
Yǐ cǐ fāngshì jiějué wèntí.
Solve the problem in this way.
Formal register; 用 could replace but sounds less literary.
用
我们用筷子吃饭。
Wǒmen yòng kuàizi chīfàn.
We eat with chopsticks.
Standard spoken usage.
以
以和为贵。
Yǐ hé wéi guì.
Harmony is most precious. (lit. 'take harmony as valuable')
Fixed expression 以…为… – cannot be replaced by 用.
以
我以筷子吃饭。
Wǒ yǐ kuàizi chīfàn.
I eat with chopsticks.
✗ Grammatical but unnatural in speech; 用 is expected in everyday conversation.

Common mistakes

Using 以 in everyday conversation: '我以筷子吃饭' sounds overly formal; use 用.
Using 用 in fixed expressions like 以和为贵: '用和为贵' is incorrect.
Treating 以 as a standalone verb: '以这本书' (✗) should be 用这本书.
Overextending 以 to cover all 'in order to' meanings in spoken Chinese — use 为了 in casual contexts.

FAQ

When do I use 用 vs 以?: Use 用 for everyday spoken and informal written Chinese when indicating a tool, method, or material. Use 以 only in formal or literary writing, especially in fixed patterns like 以…为… or to express purpose/reason.
Can I replace 以 with 用 in formal writing?: Not always. In formulaic expressions like 以政府名义 (in the name of the government) or 以资鼓励 (as encouragement), 以 is fixed. In other cases, 用 may be acceptable but would shift the register to less formal.
Is 以 a verb?: No, in modern standard Chinese 以 is a prepositional coverb. It is not used as an independent verb (unlike 用, which is also a verb). Its appearance in 以…为… is a set structure meaning 'take/use … as …'.
How do I negate 用 and 以 as coverbs?: 用 can be negated: 不用 (bùyòng, 'not using / need not') and 没用 (méiyòng, 'useless / not used'). 以 is rarely negated as a coverb in modern Chinese; negation occurs only in classical or set phrases (e.g., 不以此故).