"Could You" vs "Would You": What's the Difference?

As one of the largest online learning platforms, we get asked a lot of questions about English grammar. Today we’ll explain the difference between requests that start with “Would you” and those that start with “Could you.” For example:

Would you please close the door?
Could you please close the door?

Unfortunately, textbooks, courses, and native speakers disagree on this issue. Here are three explanations you’ll usually come across:

“Would you” is correct, because you are asking if someone will do something and not if they can do it. “Would you” also sounds more polite than “Could you.”
“Would you” and “Could you” are equally polite and acceptable ways to make a request.
“Could you” sounds more polite. “Would you” sounds more insistent and is more often used in angry requests, such as “Would you please hurry up!”

So how are English learners supposed to know which one to use?

To solve this mystery for you, we consulted some large libraries of spoken and written English and asked native speakers around our company. Below are our findings and advice.

What Does the Data Say?

When we looked at the data, we found the following.

In formal situations:

“Would you” and “Could you” are both used. For example, searching through US Supreme Court cases, we found that judges made requests with both.
However, “Would you” is more common. For example, while people making speeches say both “Would you please stand?” and “Could you please stand?”, the version using “would” is about seven times more common in subtitled speeches on YouTube.

And in informal situations:

Both “Would you” and “Could you” are also used.
In some instances, they are used with equal frequency. For example, the set phrase “Would/Could you do me a favor?” appeared almost an equal number of times in either form in libraries of modern American English and English used globally online. The number of times both “Could you” and “Would you” were used to make angry or impatient requests (e.g. “Would/Could you please just … ”) were also roughly equal.
However, in other instances, “Could you” is more common. For example, “Could you lend me …" and “Could you get me …” were two to three times as common as their “Would” counterparts.

So it seems that “Would you” and “Could you” are often interchangeable. However, “Would you” is more common in formal English and “Could you” is more common in casual, everyday situations.

What’s Our Take?

At this point, some students might think, “So ‘Would you’ is more polite, right? I’ll just use that from now on.” However, that’s not what the data says. “Would you” isn’t more polite, it’s simply more formal.

Politeness ultimately depends on how the listener interprets what you say, and given the data and our own experiences, we can guarantee you that most people will not notice which word you choose to make a request, let alone interpret it as rude.

When we asked our team, we also didn’t get the impression that people automatically found “Would you” more polite. For example, here are two responses we got:

“I actually don’t use ‘Would you’ by itself to make requests. I’m more likely to be more indirect and ask ‘Would it be possible to … ?” - Chris 🇳🇿

“I don’t actually think to say ‘Would you,’ as I don’t want to sound passive-aggressive. I searched through my email and did find one instance where I used it for a request, but that’s nothing compared to the 400+ emails where I used ‘Could you.’ - Frances 🇺🇸

So if you’re worried about politeness, focus on more important things like your tone of voice. This is also what experts at Merriam Webster and the Chicago Manual of Style say.

And if you want more practice using "would" and "could," check out our lesson on this topic, ”If I could cook, I would cook every day” with an Engoo tutor.

Finally, if you'd like to learn about the differences between other similar vocabulary, we have an article all about them: What's the Difference Between These English Words?