When do I use 成 vs 为 as resultative complements?

Use 成 in most everyday situations: 变成, 翻译成, 改成. Use 为 only in formal or literary writing, such as 变为, 翻译为, 称为. In active sentences with a human subject, prefer 成 (e.g., 他翻译成中文) rather than 为.

Can I always replace 成 with 为?

No. In casual speech, 为 sounds overly formal and unnatural. Moreover, many fixed expressions require 为 (e.g., 称为, 选为, 一分为二), while others need 成 (e.g., 弄成, 搞成). They are only interchangeable in a limited set of formal, literary contexts.

Is 翻译为 correct? When can I use it?

Yes, 翻译为 is correct in formal or written Chinese, especially in passive constructions (e.g., 这本小说被翻译为中文) or in impersonal statements (e.g., 书名翻译为英文). Avoid using it with an active human subject without 把 or 被 – in that case, say 翻译成.

Why is 为 sometimes pronounced wèi instead of wéi?

The character 为 has two pronunciations: wéi (as in 行为, 成为 – meaning 'to be, to become') and wèi (as in 因为, 为了 – meaning 'for, because'). As a resultative complement meaning 'into', it is always wéi. Be careful not to confuse them.

Easily confusedHSK 5

成 vs 为 (chéng vs wéi): choosing the right 'into'

成 (chéng) and 为 (wéi) both serve as resultative complements meaning 'into', but differ in register and collocation. 成 is neutral and widely used in spoken and written Chinese, while 为 is formal and literary, often appearing in fixed expressions and passive constructions. Choosing incorrectly can sound unnatural or overly formal.

Both 成 and 为 can follow verbs like 变 (biàn, change), 翻译 (fānyì, translate), or 改 (gǎi, change/revise) to indicate transformation or conversion into a new state or form. 成 is the default, natural choice in most contexts, especially in everyday speech and informal writing. 为 is reserved for formal, literary, or fixed expressions (e.g., 变为, 选为, 称为). In active sentences with a human subject and no passive marker, 成 is strongly preferred over 为.

When to use each

成chéng

into (transform)

Use 成 after verbs of change, translation, or conversion in all registers. It is the standard complement for 变成, 翻译成, 改造成, etc. 成 is also used in idiomatic expressions like 弄成 (nòng chéng, 'turn into') and in casual speech.

为wéi

into/as (become)

Use 为 in formal, literary, or technical contexts, especially with passive voice (被…为) or in fixed expressions like 变为, 选为, 称为. 为 often appears in official titles, classifications, or abstract transformations. Avoid using 为 in casual conversation or with a human subject in an active sentence without 把 or 被.

In some fixed phrases (e.g., 一分为二, 化整为零), 为 is required and cannot be replaced by 成.

At a glance

	成	为
Register	Neutral, used in all registers	Formal, literary, or fixed expressions only
Typical verbs	变, 翻译, 改, 弄, 搞, 变, 做	变, 翻译, 选, 改, 称, 化, 分
Active voice with human subject (e.g., 'He translates into French')	Natural: 他翻译成法语。(Tā fānyì chéng Fǎyǔ.)	Unnatural: 他翻译为法语。(Tā fānyì wéi Fǎyǔ.) — requires 被 or 把 construction for formal use.
Passive / impersonal constructions	Common: 这本书被翻译成了中文。(Zhè běn shū bèi fānyì chéng le Zhōngwén.)	Common in formal writing: 这本书被翻译为中文。(Zhè běn shū bèi fānyì wéi Zhōngwén.)
Common phrases	变成, 翻译成, 改成, 弄成	变为, 翻译为, 称为, 选为, 化为

Examples

成
请把这个句子翻译成中文。
Qǐng bǎ zhège jùzi fānyì chéng Zhōngwén.
Please translate this sentence into Chinese.
Active voice with 把; 成 is natural in this instruction.
为
这部小说被翻译为英文。
Zhè bù xiǎoshuō bèi fānyì wéi Yīngwén.
This novel was translated into English.
Passive construction; 为 is acceptable in formal writing.
成
他变成了一个完全不同的人。
Tā biàn chéng le yī gè wánquán bùtóng de rén.
He turned into a completely different person.
成 is standard for 变成 in all registers.
为
经过改革，公司变为股份制企业。
Jīngguò gǎigé, gōngsī biàn wéi gǔfènzhì qǐyè.
After restructuring, the company became a joint-stock enterprise.
Formal context; 变为 is more literary than 变成.
为
他被称为'球王'。
Tā bèi chēng wéi 'qiúwáng'.
He is called 'king of the ball'.
Fixed expression 称为; cannot use 成 here.
成
你怎么把房间弄得这么乱成这个样子？
Nǐ zěnme bǎ fángjiān nòng de zhème luàn chéng zhège yàngzi?
How did you make the room so messy like this?
Informal; 弄成 is common, 弄为 would be unnatural.

Common mistakes

Using 为 in casual speech for everyday transformations (e.g., 改为 instead of 改成 when talking about changing clothes).
Using 成 in formal fixed expressions like 称为 (should be 称为, not *称为成).
Using 为 with a human subject in an active sentence without 把 or 被 (e.g., *他翻译为中文 should be 他翻译成中文 or 他把文章翻译为中文 in formal context). The issue is syntactic, not because 为 is a preposition.
Assuming 成 and 为 are always interchangeable; in many contexts, especially in idioms (e.g., 一分为二, 化为乌有), only 为 is correct.
Writing 为 with the wrong tone (wèi) when it is the complement wéi; also confusing the complement 为 (wéi) with the preposition 为 (wèi, 'for').

FAQ

When do I use 成 vs 为 as resultative complements?: Use 成 in most everyday situations: 变成, 翻译成, 改成. Use 为 only in formal or literary writing, such as 变为, 翻译为, 称为. In active sentences with a human subject, prefer 成 (e.g., 他翻译成中文) rather than 为.
Can I always replace 成 with 为?: No. In casual speech, 为 sounds overly formal and unnatural. Moreover, many fixed expressions require 为 (e.g., 称为, 选为, 一分为二), while others need 成 (e.g., 弄成, 搞成). They are only interchangeable in a limited set of formal, literary contexts.
Is 翻译为 correct? When can I use it?: Yes, 翻译为 is correct in formal or written Chinese, especially in passive constructions (e.g., 这本小说被翻译为中文) or in impersonal statements (e.g., 书名翻译为英文). Avoid using it with an active human subject without 把 or 被 – in that case, say 翻译成.
Why is 为 sometimes pronounced wèi instead of wéi?: The character 为 has two pronunciations: wéi (as in 行为, 成为 – meaning 'to be, to become') and wèi (as in 因为, 为了 – meaning 'for, because'). As a resultative complement meaning 'into', it is always wéi. Be careful not to confuse them.