二 vs 两 (èr vs liǎng): when to use each 'two'
Both 二 and 两 mean 'two,' but they are used differently. 二 is the basic number used for counting, ordinals (like 'second'), and in compound numbers (e.g., 12, 20). 两 is used before measure words to indicate a quantity of objects (e.g., 'two people'), and in numbers like 200, 2000 when speaking colloquially. Choosing the correct one depends on whether you are stating a number or quantifying an item.
In Mandarin, both 二 (èr) and 两 (liǎng) translate to 'two,' but their usage depends on context. 二 is a pure number used in counting, mathematics, ordinals (第二, 'second'), phone numbers, and when reading digits. 两 is used before most measure words to specify a quantity of something (两个人 'two people'), and for numbers like 200 and 2000 in spoken language. The core difference: if you are just naming a number, use 二; if you are counting objects with a measure word, use 两. There are a few exceptions, such as 二两 (a fixed weight phrase), but these are limited.
When to use each
Use 二 for 'two' as a numeral: in counting, mathematical expressions, ordinal numbers (第二 'second', 二十 'twenty'), phone numbers, addresses, and when listing digits (e.g., 一二三 'one two three'). It is the default for abstract number contexts.
二 is normally not used before measure words to mean 'two of something' (e.g., say 两个人, not 二个人). The exception is a few set phrases like 二两 (a unit of weight) and 二倍 (double).
Use 两 before measure words to indicate a quantity of two items (e.g., 两本书 'two books', 两天 'two days'). It is also common for the numbers 200 (两百) and 2000 (两千) in spoken Chinese, and in expressions like 两点钟 (two o'clock).
两 is never used for the ordinal 'second' (use 二, as in 第二). In numbers like 2万 (20,000), both 二万 and 两万 are acceptable, but 两万 is more colloquial. For 20, 二 is used (二十), never 两十.
At a glance
| 二 | 两 | |
|---|---|---|
| Before measure words (e.g., 个, 本, 天) | Rarely used (except set phrases like 二两) | Standard usage (两个人, 两天) |
| Ordinal numbers (second, second lesson) | Used (第二, 二月 'February') | Not used |
| Numbers 200 and 2000 | Accepted (二百, 二千) – more formal | Accepted (两百, 两千) – more common in speech |
| Reading digits (phone numbers, serials) | Used (一二三) | Not used |
| Compound numbers (20, 12) | Required (二十, 十二) | Not used |
Examples
- 二第二课dì èr kèLesson two (the second lesson)Ordinal – only 二 is correct.
- 两两个人liǎng ge rénTwo peopleQuantity with measure word – 两 is required.
- 二电话是12345678。Diànhuà shì yī èr sān sì wǔ liù qī bā.The phone number is 12345678.Reading digits – use 二, not 两.
- 两我买了三本书，他买了两本。Wǒ mǎile sān běn shū, tā mǎile liǎng běn.I bought three books, he bought two books.Quantity with measure word 本.
- 二二两是多少克？Èr liǎng shì duōshǎo kè?How many grams are in two liang?Fixed phrase – exception to the rule: 二 used before a measure word (两 is a weight unit).
Common mistakes
- Using 两 for ordinals: ✗ 两第二 (correct: 第二).
- Using 二 before most measure words: ✗ 二个人 (correct: 两个人).
- Using 两 in compound number 20: ✗ 两十 (correct: 二十).
- Using 二 for informal 200 when speaking colloquially: not strictly wrong but 两百 sounds more natural in speech.
- Thinking 二两 breaks the rule: it is a fixed phrase for a specific weight measure, not a general pattern.
FAQ
- When do I use 二 vs 两 before measure words?
- Use 两 before measure words to mean 'two of something' (两个人, 两本书). 二 is rarely used for this purpose, except in set expressions like 二两 (a unit of weight) or 二倍 (double).
- Can I use 两 for ordinal numbers like 'second'?
- No. Ordinal numbers always use 二: 第二 (the second), 二楼 (second floor), 二月 (February). 两 is never used for ordinals.
- Why is 二两 an exception?
- 二两 is an exception because 两 here is a measure word for weight (liang, about 50 grams), not a quantity. The number precedes the measure word in this fixed phrase, so it uses 二 instead of 两.
- Is it 二百 or 两百?
- Both are correct. 二百 (èr bǎi) is more formal and common in written Chinese; 两百 (liǎng bǎi) is more colloquial and frequently used in speech. Same for 二千 vs 两千.