比 (bǐ) is the everyday way to say that one thing is bigger, colder, cheaper or better than another. The pattern is short, but it has two rules that learners often break: no 很 before the adjective, and no 不 for the negative.
A + 比 + B + adjective. Read it as "A, compared with B, is ...". The adjective comes at the end, and there is no word for "more": 我比他高 already means "I am taller than him".
A and B should be the same kind of thing. To compare my phone with yours, say 我的手机比你的新; the 的 at the end stands for 手机, so you don't need to repeat it.
The most common mistake is to put 很 or 非常 before the adjective, as in 他比我很高. With 比 the adjective stands on its own: 他比我高.
To say how big the difference is, add something after the adjective: 一点儿 for "a bit", 多了 or 得多 for "much", or an exact amount such as 三岁. To say "even more", put 还 before the adjective.
To say "A is not as ... as B", use 没有 instead of 比: A + 没有 + B + adjective. You can add 那么 before the adjective, meaning "as ... as that". Don't say 我比他不高.
For a yes-or-no question, add 吗 at the end of a 比 sentence.
To compare actions, use a verb with 得 and put 比 either before the verb or after 得. Both word orders are correct and mean the same.
Practise this grammar point on paper: 20 exercises using only HSK 2 words, with an answer key on a separate page. Free to print and copy for your class.
Every example on this page uses only words up to HSK 2. Paste your own sentences into the level checker to see which words, if any, are above your level.