有点儿 and 一点儿 are both translated as ‘a little’ or ‘a bit.’ Since they appear to have the same meaning, are they interchangeable, in all situations?
The answer is NO.
Then how are the two expressions used differently?
Well, they can modify adjectives, verbs and nouns, but they do have some other important exclusive uses.
a. 有点儿 should be stated before the adjective, while 一点儿 is always stated after the adjective.
I’m a bit tired.
I hope it will be a bit cooler tomorrow.
b. 有点儿 expresses a negative feeling or complaint, while 一点儿 expresses a hopeful feeling.
This shirt is a bit too big, do you have smaller ones?
TV is a bit too loud, could you turn it down a bit?
This dish is bit too light, could next dish be a bit saltier?
一点儿 + noun is a noun phrase, while 有点儿 + noun is a verb phrase. Why? because 有点儿 is actually the shortened version of 有 + 一点儿. Therefore, 有点儿 + noun can be used in the following two types of sentences, however, 一点儿 + noun cannot be used in these sentences.
a. 有点儿 can be used in ‘there is’ sentences.
There is a little bit of milk in the refrigerator.
冰箱里有点儿牛奶 = 冰箱里有一点儿牛奶。(correct)
b. 有点儿 can be used in ‘have’ sentence.
Please have some confidence in her!
请对她有点儿信心 = 请对她有一点儿信心。（correct）
c.一点儿 + noun can follow a verb, and thereby become an object; 有点儿 cannot do this.
I want to drink a little beer.
有点儿 can modify verbs indicating a mental state or an emotion: like, hope, regret, worry, miss, etc, and must be placed before the verb. In contrast, 一点儿 is used to modify common verbs such as add, read, write, wear etc, and must come after the verb.
Examples for 有点儿:
I miss my hometown a bit.
Examples for 一点儿:
I watched this movie a bit.
I don’t like this movie at all.
I was very busy today, but I was not tired at all.
She is not beautiful at all.