A very busy professor just responded my email. He answered my questions, and in the end, he explicitly said something like "Please let me know if you have any questions" or "Please respond if you have further questions".

So, I am trying to think as if I am in his shoe. Is he not expecting me to reply to this email, if I do not have any further questions?

Is it impolite if I do not respond to this email and let it go? Or, is it considered impolite if I spam his "already-too-full" mailbox with a generic "Dear XXX, Thanks for XXXXX, Regards, XXXX" ?

  • 81
    Reply and thank him. Don't overthink these things. Commented Feb 8, 2018 at 2:43
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    Courtesy isn't a waste of time.
    – user9646
    Commented Feb 8, 2018 at 8:42
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    I think this question gets to something at the heart of learning how to navigate a rank hierarchy as a confident, considerate adult. It can be hard to learn the difference between respecting someone else and disrespecting yourself. Devaluing yourself leads people to assume their actions are mostly disruptive and they should avoid interacting unless it's absolutely necessary.
    – kmc
    Commented Feb 8, 2018 at 19:01
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    Does anybody not appreciate being thanked? Commented Feb 9, 2018 at 16:57
  • 3
    Possible duplicate of Etiquette on sending a thank you e-mail to respondents who gave me helpful information
    – G M
    Commented Feb 12, 2018 at 8:51

8 Answers 8


If you send a thank-you note, in addition to being polite, you let the professor know that you received their email and don't need anything else from them. That lets them avoid trying to follow up with you later.

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    This is a good, practical reason for why sending a quick thank you is helpful. I send lots of emails in my job, and when I don't get a response I tend to wonder if anyone got it, if it was useless, etc. When I do get a quick thank you, it takes me all of 2 seconds to read and delete/archive and now I'm freed from thinking about it in the future. Commented Feb 9, 2018 at 18:46
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    So much this. It is not the thank you that I appreciate most, but the acknowledgement. Whether or not this particular professor will care in this particular case, it is generally incensing when you do care. The fact that the text is "thank you" rather than "receipt acknowledged" is icing on the cake. And, well, it doesn't hurt, does it? Commented Feb 10, 2018 at 16:05

A thank you for a quick response is usually appreciated to show that the time spent was worthwhile. It makes people feel better. So there's absolutely no reason not to send one, if you so choose.

The formality of your email should be relative to where you are: if you expect formality (as in Germany), you'd still include the "Dear X" header; in places where it's less formal, such as many US universities, you can dispense with the salutation.

  • I agree but I'd provide more guidance -- the short version of a thank-you email dispenses with the big greeting. It can be short and sweet, e.g. Thanks for the link -- looks extremely helpful. (For example.) Commented Feb 8, 2018 at 4:01
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    Depends on where you are: for instance, in the US, sure; in Germany, probably not.
    – aeismail
    Commented Feb 8, 2018 at 4:03
  • The reason not to send one is if the message conveys 0 information and wastes their time. But it depends on the conversation. If it was a simple query->response, a standalone thank you is unnecessary. If it was a multipart conversation, with investment on both sides, it is definitely warranted.
    – John K
    Commented Feb 9, 2018 at 21:58
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    Indeed. I start to always send out Thank-you mails after one professor followed-up one of his un-responded email.
    – dodo
    Commented Nov 29, 2020 at 6:39

Professors receive hundreds of emails every day. Adding a dozen thank-you emails won't help them to scan their emails for stuff they need to know or need to answer.

I'd propose to save the thank you for the next time you meet them in class or on the hallway. Still polite, but not a waste of their time.

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    I'm almost tempted to say that the satisfaction of being able to click an email and realize that it needs no extra handling (like a thank-you email) might outweigh the extra burden of clicking on it...
    – user541686
    Commented Feb 8, 2018 at 9:40
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    So instead of telling them thank you in a way that they can deal with it in their own time, when they want, you do it in a way that demands immediate attention and requires more thought (who's this student, why are they thanking me...)? And you claim this is to save time?
    – user9646
    Commented Feb 8, 2018 at 12:24
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    The burden of having to sift through reams of email trying to pick out the ones you think are important enough to read is FAR, FAR greater than Mehrdad/Najib perceive. Additionally, some people are interrupted from their work when email arrives. Thus, it is absolutely an annoyance to click on an email to find that the only reason for its existence is Thanks. In the business world, it is understood by nearly everybody not to do that. With that said, if you really feel that a person went above and beyond then you should send a corresponding above and beyond thank you if you choose to send one.
    – Dunk
    Commented Feb 8, 2018 at 20:46
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    Seeing how its 2018 and most, if not all, email clients have threads, I dont see how responding with an "thank you" could prevent the busy professor to scan their emails efficiently.
    – Jakob
    Commented Feb 9, 2018 at 10:43
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    @Jakob I don't see how threading improves things in this case. You still have to read the e-mail to tell if it contains "thank you" or a page full of text describing a major problem. Commented Feb 10, 2018 at 15:30

tl;dr- Usually it should be okay to send a concise thank-you email.

Three categories:

  1. Most recipients would likely enjoy a concise thank-you email for the reasons others have mentioned: the cost to them is pretty low while the appreciation can be nice.

  2. Some recipients may really enjoy a thank-you email. Especially if they're having a bad day and just need a distraction, a little gesture like that can mean a lot.

  3. Some recipients are so flooded by emails that they end up not even reading a lot of their mail. They're unlikely to get mad at anyone for sending them a nice thank-you email, however it'd still be easier for them to not get anything unnecessary.

Usually, it's probably safe enough to send a concise thank-you email. It'll backfire only a bit in the case of Category (3), which is probably the least common case, and even then it seems unlikely to be any sort of significant issue.

It's probably hard to guess who might fall into Category (3) unless you personally know them.

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    Most of the professors I know are of category (3). So no; don't write emails.
    – usr1234567
    Commented Mar 11, 2018 at 14:53
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    @usr1234567 While that was my first thought, too, I suspected that individuals tend to have pretty significant sampling bias. Category (3)'s likely more common at competitive research institutions, while Categories (1) and (2) may be more prevalent at non-competitive research institutions and non-research institutions.
    – Nat
    Commented Mar 12, 2018 at 8:12
  • @usr1234567 Yes, I agree. Most of the professors and almost all of the big professors are at category (3).
    – dodo
    Commented Nov 29, 2020 at 6:44
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    @Nat Even if it is a non-competitive institute at USA, the professor is still likely to receive a lot of communication from students interested in research all over the world. Hell, even some postdocs with a few publication receive tons of emails.
    – dodo
    Commented Nov 29, 2020 at 6:45

It depends on how much work the professor put in to their message.

If you asked

What is the weight of an unladen African swallow?

and the professor responded, two months later,

As your question interested me greatly, I just went on a field trip to find out. Draft paper attached.

then of course a "Thank you" is appropriate.

The opposite situation is when thinking about and archiving your "Thank you" email would take a significant percentage of time compared to the time it took to answer your question in the first place.


Send the thank-you.

I'm not in academia but I often write emails to colleagues to explain concepts or systems that aren't specifically my area but where I hope to be helpful. I put a lot of thought into the them and try to provide a useful explanation and reference info.

Commonly I'll send a write-up to a whole team and get no feedback. I wonder for a moment if it was worth anyone's time to read it through, then shrug and move on. It's useful to have written the explanation because it's good practice and helps to organize my own thoughts, so I don't generally sweat it.

But occasionally I'll get a quick thank-you. Or months later someone will casually mention that my email has become their go-to reference for details on the topic. And that gives me motivation to keep researching and sharing knowledge.

when you take time out to help someone, move on, and then find out that you've made an impact, it's a really nice moment.


I enjoyed reading the back-and-forth here in the thread, and I especially like the point about considering the depth of the response and how specifically it fit with the sender’s question.

Something I find unconscionably rude is a scenario like this:

Student sends detailed email with multiple questions.

I take the time to craft a specific, point-by-point response that addresses each part of the student’s question, along with stat examples and/or code (I teach Data Science)

30 mins later student writes ANOTHER detailed series of questions, with a new subject line and NO acknowledgement of my previous answers.

I’m not even necessarily going for a ‘thank you’ here - even a ‘got it’ would go a long way. This isn’t the right way to behave with anyone - peer, senior, or subordinate.

My way of handling this is to simultaneously teach some manners and pump the brakes on the exchange. I ask them to clarify whether they received the first one, mention that i can check with IT if there might be a problem with messages going through, etc. and then wait for that response before diving into the next round.

  • I agree. Acknowledgement is always appreciated!
    – dodo
    Commented Nov 29, 2020 at 6:38

"... if you have questions ..." states a condition to be satisfied if you wish to respond. Therefore, if you have no further questions, you need not respond. Someone has to end an email exchange and in this case he ended it, unless you have more questions.

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