When to Use "Liang" Versus "Er" in Chinese

There are two ways to say "two" in Mandarin Chinese: 二 (èr) or 兩 (traditional form) / 两 (simplified form) (liǎng). These characters cannot be used interchangeably so it's important to know when it is appropriate to use which form.

Here is a guide to understanding which scenario calls for what kind of "two."

With Measure Words

兩 / 两 (liǎng) is used with measure words such as 個 / 个 (ge) or 本 (běn). For example: 

兩個人 / 两个人 (liǎng ge rén) – two people
兩本書 / 两本书 (liǎng běn shū) – two books

However, if a measure word is used in conjunction with numbers ending in two, like 22, 102, 542, the 二(èr) form is used. For instance:

二十二個人 / 二十二个人 (èr shí èr ge rén) – twenty-two people
一百零二本書 / 一百零二本书 (yī bǎi líng èr běn shū) – one-hundred and two books

Some numbers will include both kinds of "two." For instance:

兩千兩百零二 / 两千两百零二​ (liǎng qiān liǎng bǎi líng èr) – two-thousand, two-hundred and two

Counting Numbers

二 (èr) is used when counting without measure words. For example:

一, 二, 三 (yī, èr, sān) – one, two, three

十，十一， 十二 (​shí, shí yī, shí èr) – ten, eleven, twelve

二十，二十二，二十三 (èr shí, èr shí èr, èr shí sān) – twenty, twenty-one, twenty-two

Counting Measure Word Numbers

Some numbers are also used as measure words. For example, 百 (bǎi), 千 (qiān), 萬 / 万 (wàn) are measure word numbers. Respectively, the characters mean a hundred, thousand, and ten thousand. In those cases, numbers like two-hundred, two-thousand, and twenty-thousand take the 兩 / 两 (liǎng) form:

兩百 / 两百 (liǎng bǎi) - 200
兩千 / 两千 (liǎng qiān) - 2,000
兩萬 / 两万 (liǎng wàn) - 20,000