I understand that it is not a good idea to speak more after your time is out during a conference presentation. So we generally distribute our total times among each slide depending the contents and priority during the preparation. But sometimes what happens one/two particular slides take little more time. As a results your time goes out before summarizing your presentation.

So I sometimes skip my summary and acknowledgement slides to avoid the loss of discussion time. I am wondering whether this is a good idea, or whether I should finish my talk with more 30–40 seconds?

  • 55
    Rehearse. Rehearse. Rehearse. Edit down to fit the available time. Repeat. If you can't do the pitch within the stated time, you're saying too much.
    – keshlam
    Commented Sep 10, 2015 at 14:44
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    If you take 30-40 seconds longer, that's 30-40 seconds you are taking away from the speaker after you, unless you come right before the coffee break. Commented Sep 10, 2015 at 15:42
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    @StephanKolassa In the latter case you are stealing 30-40 seconds from the coffee break. That could make some people really mad! ;-) Commented Sep 10, 2015 at 19:33
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    There seems to be an implicit assumption in the question that each slide in a talk should normally take the same amount of time. But that would just be silly. Some slides need only five seconds; others need five full minutes. The only thing that matters is the total length of the talk.
    – JeffE
    Commented Sep 10, 2015 at 21:30
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    Do not skip your acknowledgement slides. Especially if you are working in a large collaboration, it is discourteous. I remember when people don't thank me for my contributions, and I am sure to repay the favour. ;) I would put the acknowledgement slide near the beginning, so it is out the way quickly. (By the way, I am not saying you should spend five minutes on that slide. I am just saying, show the slide, say thanks, make your joke about getting your excuses in early, move on. But everyone is happy that you thanked them properly.)
    – Calchas
    Commented Sep 10, 2015 at 22:11

11 Answers 11


First, some conferences have really strict timing and you will be given no extra time.

Second, if there is important slide or two, just do it. But make sure that you only slightly extend your time (e.g. 10%). If you are going to extend it by 50%, or 200% (I saw that, and I was pissed at both the speaker and even more - the chair for allowing that) - please, don't.

Side note: as a chair I am an ass. And while I give something like 1 min grace time (for 15 min talks), then after that:

speaker: "But there is an important slide afterwards!"

me: "But not as important as other participants' time."

EDIT: By all means I recommend rehearsing and finishing on, or before, time. I only answer the question - whether to use extra 40 sec for 2 unfinished slides or not. "You should prepare to avoid such situation" is as on-topic as "you should go fishing instead of attending a conference".

(If the question is "Given X, should I do A or B?" all legitimate answers should assume "X", even if it is a suboptimal/nasty/unprofessional/embarrassing situation.)

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    +1 for the last line. If only that happened more often.
    – Chris H
    Commented Sep 10, 2015 at 13:39
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    That's not being an ass – that's preventing the speakers from making asses out of themselves.
    – J.R.
    Commented Sep 10, 2015 at 15:22
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    In grad school we learned a cool trick for chairing sessions that have speakers who won't stop at the appointed time. After showing the 5 minute and the one minute warning, if the speaker makes no sign of stopping you get up (you have to sit in the front row) and stand, smiling, with your arms crossed. Every 10 seconds you take a step towards the speaker. Normal people stop immediately after the first step (you are invading their space), most stop after 3. Once you are close enough to grab the mike, do it and thank the speaker and carry on. Commented Sep 10, 2015 at 17:33
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    A 10% overrun is pretty significant: you shouldn't even do that. Look at it this way: unless your talk is pretty awesome, you've lost a large fraction of the audience by the end. And, let's face it, if you're overrunning, your talk probably wasn't all that awesome. So a 10% overrun on a 20-minute talk is asking a large fraction of the room to sit there being bored for two more minutes. Try it: sit and do nothing for two minutes. That's an eternity. Commented Sep 10, 2015 at 21:03
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    if there is important slide or two — Then show them first.
    – JeffE
    Commented Sep 10, 2015 at 21:34

As a rule of thumb you should aim your presentation to be finished 2 to 3 minutes before the allotted time. This way, slight delays like the ones you mention (in the sub-1-minute range) should not require you to skip any material or cut into the discussion time.

However, even if you do not do this, cutting 30 seconds of discussion seems like the lesser evil as compared to skipping over slides, which is often perceived as a sign of a badly prepared talk (at least in my circles skipping slides is considered at least slightly unprofessional). Even if this is not the case, 30 seconds of discussion seems like such an irrelevantly short time that I can't imagine changing my presentation for it (in slightly larger conference halls it may take the student volunteer longer than 30 seconds to get a microphone to a person asking a question).

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    This. Don't plan to be on time. Plan to be under time.
    – Fomite
    Commented Sep 10, 2015 at 18:16
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    Never go over time. Never. That's really it. Harsh but true. If you're routinely going over time, you're saying too much, or saying it wrong. Always plan to end 1 minute early. Re-think what you're saying. I go to conferences where people present slides and slides full of text. Nobody but nobody reads this stuff, let alone memorises it. Cut that stuff out. If you absolutely have to present tables, references, etc etc, this should be kept to a minimum, like two slides. Ideally, ditch all that stuff, you and your talk will be far, far more memorable. Commented Sep 11, 2015 at 11:24

In general, I would try to adhere to your presentation time as closely as possible. If all that's left are summary or acknowledgment comments, I'd simply leave them up on the board while the first questions are being asked. However, if you have a critical content slide—the one that delivers your "punchline"—that you haven't talked about, then you should use the time.

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    "However, if you have a critical content slide (...) then you should use the time." - or better yet, do not place it at the end of the presentation. Presentations are not mystery films that rely on giving away as little as possible until the very end to keep up the suspense. This doesn't mean that a talk should be boring, but the goal of a mystery movie is to open up more questions along the way and possibly provide a few red herrings, whereas the goal of a conference talk is to gradually answer questions. Commented Sep 10, 2015 at 14:48
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    +1 for @O.R.Mapper's comment. The punchline should come first if possible, or at least early, but certainly not last.
    – JeffE
    Commented Sep 10, 2015 at 21:36

You should probably not skip your summary talk. If you are running out of time you should notice this early, and skip some of the previous slides so you can get to your summary on time. Regarding obviously skipping slides looking unprofessional, you should use something like the Presenter View on PowerPoint if possible, so you can skip slides or show other slides of more interest to your particular audience without them seeing you run through everything.

You don't need to read out your acknowledgements. Few people want to hear them, especially if it takes away time from actually presenting your science in a short talk. Just put them on screen as you finish.


But sometimes what happens one/two particular slides take little more time. As a results your time goes out before summarizing your presentation.

It's easy to see how this could happen. Somewhere in your talk, you have the nitty-gritty details, and it's hard to rush through that material.

Perhaps the best way to address this is by adding some slack time to your presentation, either by finding a way to get through the other slides in less time, or by finding a slide or two that can be removed from the presentation altogether.

So I sometimes skip my summary and acknowledgement slides to avoid the loss of discussion time.

I think you can get away with not talking all the way through an acknowledgement slide. There's a good chance that most folks in the audience won't know who those people are anyway, and hearing their names isn't going to change anything. You can always put their names up, along with where they are from, and say something like, "Without the hard work of these talented associates and colleagues, this research would not have been possible," and leave it at that – particularly if time is a precious commodity.

Skipping the summary seems like a bad idea, though. You should be able to pace yourself so that you have a minute or two to summarize your accomplishments.


Plan your presentation so that about 10% to 20% of your time and slide allotment is optional detail material. Schedule this material right before your summary and conclusion, which should be really well timed. Once you only have time for your conclusion + 30 seconds or so, quickly wrap up your current slide and run through your conclusion. You will look really professional by finishing up a few seconds before your time is up - which reputation will result in more invites to present.

The real kicker is that all those extra slides never go to waste - they are slides for the inevitable questions that your audience will ask. Whther in the presentation hall or the bar afterwards, as professional as finishing on time is, wait until your audience sees you pull up a slide to address every question asked.


I have a few suggestions; first, if this really happens that you are out of time with only the summary slide remaining, just show the slide. Maybe only speak about it for a second and leave it up for people to read while you answer questions.

Really what you do is be conscious about your remaining time during the talk. If you are getting close to the end, and close to running out of time, maybe skip an earlier slide or a proof so you can make sure to get to your conclusion.

Taking 30 seconds or a minute over is usually fine. Whoever is chairing the session should be giving you a time warning, and then you can quickly finish up. If they have to warn you more than once that you are out of time, you will be making a poor impression on the audience.


Not all conferences are equal. In some smaller workshops it is often perfectly alright to speak a little bit longer, and 40 seconds should not be a problem at all. In such smaller conferences and workshops, people often discuss rather freely and in detail on various aspects, and there is usually no need to maintain an excessively strict time schedule, except for the respect for the organizers, the chairperson and the colleagues - which are all doubtlessly important.

One may also observe how such cases have been handled in previous sessions (from my experience there is always at least one speaker who is not respecting the time schedule). In such smaller conferences it is also sometimes tolerated to interrupt the speaker with a question, and the time used for this interruption should obviously be taken into account by the chairperson.

In other cases, such as large conferences with parallel sessions, timing is absolutely crucial and I would rather stop the talk at most 30 seconds after the "red light bulb" goes on than trying to hastily convey all the information that I had originally planned to present. Fortunately I don't remember that this has ever happened to me. In such situations, which of course can and should be avoided with appropriate rehearsal, I would rather skip a result or an entire subtopic of the talk than the acknowledgments. The summary does not necessarily require an explanation if there is no time left and I agree that it may be sufficient to show it as final transparency; but I think that the acknowledgments are more important. One possibility to avoid such a situation is to acknowledge the coworkers and the funding agencies at the beginning of the talk.


It comes down to how well you prepare. After practising a trial version of your talk with own research group and taking on board their changes, it's well worth practising again. This could be in front of the same group, but better to grab some people at a similar level who might be interested either in the work itself or in you returning the favour (especially important for postgrads, help each other out). Then you'll get a much better feel for your real timings.

If you have a good summary slide, just displaying that as you finish can gain you a minute or so as well.


If you tend to go over time then you are not pacing yourself throughout the presentation.

When preparing for the presentation you should determine when you are showing each slide throughout the presentation. Don't assume however that every slide will take equally long to talk about. A sequence of 5 diagrams (explaining a sequence of events for example) can take as long as a single list.

During the presentation keep an eye on the timer and when you notice you are lagging behind you can then say less about some less important slides. Conversely if you are getting ahead you can talk some more about the important ones (or just let it spill over into the questions slot).

Prepare those optional sections ahead of time while scripting out your talk.


Keep a timer and have a trigger that tells you when you have two or three minutes left. A vibrating alarm on a watch or cell phone is best. If you haven't gotten to the punch line yet, go there now.

You've now got a minute to rush through the remaining preamble, and then you have a "luxurious" minute or two to cover that point that you want to hit.

This is beneficial for two reasons

  1. You don't look like a hack by going over and
  2. In the scenario where you go over, you are rushing through what you think is the most important part of the presentation. That you aren't getting there until slide n-1 is a another topic, but if you give truncate something in the middle of the talk, you can then give your punchline the time it deserves.

Now, the discussion period will probably involve you answering questions by showing those middle slides you rushed through, but you're now being respectful by sticking to time and controlling the conversation. Win-Win.

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