This website says "Can you cook?" means "Do you know how to cook?" and that "Are you able to cook?" means "Do you have time to cook?"

Does that mean that you use "Are you able to" if you want to ask someone to help you instead of "Can you"?

A) Can you help me with my homework? B) Are you able to help me with my homework?

Does that mean B is better? But A sounds more natural to me though I'm not very sure because I'm not a native speaker.

On what basis I should decide which to use, "can you" or "are you able to"? When are they different and when are they the same?

  • Assuming that the person has the knowledge to be able to help with the homework, the polite way to ask a favour is "Will you...?" (are you willing?), preferably followed by "please". However, if you know the person well it's quite common to use "Can you" or "Could you" to ask a small favour. In this context it doesn't mean "Are you [physically] able to?" Commented Nov 1, 2021 at 9:38
  • ...and if you asked "Are you able to help me" it would probably be understood to mean "Can you spare the time right now?" (or at the time the speaker plans to do their homework). Commented Nov 1, 2021 at 10:21

2 Answers 2


In common usage there’s really very little difference between the two. I’d slightly lean towards ‘can you’ but others may prefer ‘able to’. I’d also consider ‘could you’ and ‘would you’ to be more polite, but others may disagree. If you want to be as polite as possible, set up the question by asking ‘are you busy’, then show some interest in what they are doing, then ask how they feel about helping you.


I understand the distinction that the website is trying to make, but I don't think it really exists. In the particular example it gives (my wife is asking about the possibility of me cooking a meal for friends, knowing that I may be short of time) Then "Can you cook for our friends on Saturday." seems correct and idiomatic, and has the same meaning as "Are you able to cook ...."

In your example, again I don't see much difference in meaning between "Can you help me" and "Are you able to help me". Using "can" also raises the matter of possibility and not just ability.

Can you help me with my homework?

Not right now, I'm cooking dinner.

It would be odd to use "Are you able to..." in that context, as it is more formal and this is a home-life context, and the child wants to know not only about the parent's ability, but also the possibility. It would be wrong for the parent to answer "Yes I can." and then not try to help the child. The question is not really about if the parent "can" help but if the "will" help.

The main reasons to use "are you able" are 1) to use tense

I will be able to help you with your homework at the weekend, and I was able to help you last weekend.

And 2) to avoid the meaning of "is it possible" or "is it permitted" that "can" implies.

Am I able to still play tennis?

(a patient asking a doctor about their ability to play with an injury, and not asking for permission)

Finally, 3) The "be able" form can add a little formality

I am able to program in Java and C.

(formal writing in a CV or resume)

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