Most (probably all) universities attribute to each subject a fixed number of credits, which in turn are [most of the time] related to the time spent in classes.

In Brazil, the majority of courses are worth 60 credits and lectures are 120 minutes long. During my undergrad (physics) I've watched several lectures from all over the world to help me study, many of them from the US, India and the UK. I've noticed that the lectures in the US and UK were rarely longer than 85-90 minutes, while in India they had most of the time the same duration as in Brazil (120 minutes). I felt that teachers in the US/UK covered less subject in their lectures, but at the same time it seemed as if they had covered exactly what could have given you a hard time studying on your own: intricate details of a proof, obscure references, hints to particular exercises, etc. In Brazil/India it just looked as if they were reading the book and explaining each and every little detail. The result was that, even though the 85 minute lecture covered specifically less than the 120 minute one, I had the impression that I learned more from it, and that it [obviously] made me feel less tired.

I've taken several courses in physics and mathematics and, from my experience, I simply cannot stay focused for more than ~75 minutes in a lecture. I'm therefore wondering how does it work in countries all over the world. Studies like this one show that an even shorter lecture might be as effective as a longer one, and this layman review points out that people can only focus for 15 minutes in a row. This suggests that the optimal length of a lecture should not exceed one hour (perhaps much less), with breaks such that students can assimilate what's being taught. Is there a country where lecture time approaches such patterns, or where other strategies regarding lecture length optimization are employed?

  • Comments are not for extended discussion; this conversation has been moved to chat.
    – eykanal
    Commented Nov 21, 2016 at 2:24

7 Answers 7


Well in the UK we usually have 50 minute lectures of which we might have 2-3 per week on each subject. The evidence from educational research that I have read is that you can't stay focused listening for more than 20 minutes in a lecture so even in a 50 minute lecture it is good practice to break it up with something a bit different in the middle.

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    By "we" do you mean UK higher education as a whole, or you and your coursemates? In my experience of studying in the UK, 2-3 50min lectures aren't uncommon, especially at first year level, but longer, less frequent, lectures are pretty common too.
    – Ian_Fin
    Commented Nov 16, 2016 at 16:06
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    This is highly department and university dependent (my former department made frequent use of 2 hour lectures). Maybe provide some links to timetables showing no 2 hour lectures.
    – StrongBad
    Commented Nov 16, 2016 at 17:09
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    Given that the basic UK undergraduate terms can run anywhere from 8 to 12 weeks, with some institutions overlaying a semester system on top of that, expecting any standardisation in teaching schedule is rather hopeful.
    – origimbo
    Commented Nov 16, 2016 at 23:13
  • @StrongBad How about maths.cam.ac.uk/system/files/partiaweb_4.pdf as an example of a degree with only one hour lectures [50 mins in practise] (It's this year's Cambridge Cambridge first year timetable, previous years aren't significantly different)
    – origimbo
    Commented Nov 16, 2016 at 23:29
  • @origimbo I can confirm that first year maths lectures in Cambridge were in one hour slots in the 1982/83 academic year.
    – Mike Scott
    Commented Nov 17, 2016 at 11:33

The 15 minutes timespan fits pretty well to lecturing on blackboards in several classrooms I taught. If usually takes me about 15 minutes to fill the blackboards (larger rooms have larger blackboards but need larger writing, leading to a constant scaling of the time) and since our blackboards in Germany often have an abrasive-blasted glass covering they are cleaned best with water and a squeegee. This takes some time and I happily invest that time with the benefit of clean blackboards, no dust in the air and a little bit refreshed students (downsides: smudgy hands, dirty shoes and sometimes slippery grounds…). For a 90 minutes lecture, as we have here, this gives about 5 cycles of 15 minutes teaching and some minutes cleaning.

On a different note: First year students who come from school are more accustomed with 45 minutes lessons and one sees that most student need some weeks to adapt to the longer lectures (even though there are the cleaning breaks) but most students in fact do adapt.

  • 2
    When I started undergrad I couldn't stand more than 60 minutes sitting there and listening. I could actually pay attention to no more than 45 minutes, as you said. By the second year I could already face 90 minutes with no problems, but nowadays, in my PhD, I can barely sit for half an hour. Also, I'd like to congratulate you for your effort to make your lectures easier to digest - I was only done with being a student one year ago, so I remember very well how terrible it is to have a teacher that doesn't care. Commented Nov 16, 2016 at 17:50

In Scandinavia, many lectures are timed roughly like a football match: 2x45mins, with a 15mins break in the middle. I have generally found this pretty effective, both as a lecturer and as an audience member.

(My first-hand experience of this is just in mathematics at Stockholm University, but I’m told by colleagues that this is pretty standard in other subjects and departments in Scandinavia.)

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    Scandinavia: always in the forefront of progress. Commented Nov 17, 2016 at 12:44
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    45 minutes is the standard "hour" in Greece, too, with 15 minutes breaks. Lecturers are free to "customize" 2-hour lectures into a single unit without break or a 3-hour lecture into 2 units with one break instead of two, usually after discussing with the students. Commented Nov 17, 2016 at 14:37
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    Poland has the same as Greece.
    – kubanczyk
    Commented Nov 18, 2016 at 10:34
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    this is the same in EPFL, Switzerland Commented Nov 24, 2016 at 10:51

In an ideal world, the duration of the lectures would be commensurate to the attention span, and the schedule would be geared toward the maximum learning efficacy.

In a real world, duration and schedule are frequently determined by other constraints, e.g, the structure of the education system which can impose a minimum amount of credits or hours, the available rooms in a university, or the tradition. And these constraints make it difficult to adapt duration and schedule to the continuously changing attention span. If twenty years ago the attention span was around 45 min, nowadays it is around 20 min: how to deal with this variability in a practical way?

Moreover, determining whether a certain system is really more efficient than another can be quite difficult: after all, in the long run, several different educational systems, with different lecture duration and schedules, have been able to produce a steady flow of good graduates.

In my country, Italy, the duration of the lectures and the number of lectures per day vary in a wide range depending on the faculty. Duration typically ranges from a minimum of 1 h to a maximum of 4 h. The number of lecture hours per day can be up to 8.

In my university, up to a few years ago, there were two possible durations: 2 h or 4 h. Then we moved to a schedule with 1.5 h or 3 h lectures.

In the old system there was usually 1 break for the 2 h lecture and 2 or 3 breaks for the 4 h lecture (it is not clear from your question whether your 2 h hour lectures have, too, a break in the middle or not). In the newer system there is usually no break for the 1.5 h lecture and 1 break for the 3 h lecture.

As a student, I experienced the old system; as a teacher I have experienced both systems. When I was a student I also attended lectures in another faculties (e.g., humanities, maths and physics) where the lecture duration was of 1 h.


  1. 4 h lectures are exhausting and inefficient from both point of views, that of the students and that of the teachers.
  2. At the other end, 1 h lectures can be too short in certain cases. For instance, if I have to explain how a complex instrument works I want to have enough time to complete the main parts, drawing the complete block diagram. For this, sometimes, 1 h is not enough.
  3. The 2 h lecture with a 10-15 min break in the middle seems to me the best option for both parts for many subjects. Students were relatively fresh at the end of the lectures and 2 hours gave me enough flexibility in the arrangement of the topics. With a 10-15 min break, each part of the lecture has an effective duration of about 50 min, longer than the present attention span, but not overwhelming with a bit of habit. This duration seems almost in agreement to the pattern you suggest.
  4. The 1.5 h hour lecture without breaks is a bit too long, and I can see the students drifting toward the end (for various reasons, I cannot put a break in the middle).
  5. Independently from the overall duration, many students use breaks to ask questions, thus keeping concentration.
  6. Finally, it is my impression that a lot depends on the structure of the whole path, from elementary school to university. I was used to 4 h lectures also at the high school so, though exhausting, I didn't considered anomalous finding 4 h lectures at the university, and I was trained for that.

I would highly doubt that any large universities regularly utilize a nominal lecture duration of less than 1 hour. Typically in the US and UK, a nominal 1 hour lecture is only 50 minutes with the extra 10 minutes allowing students to get from one class to the next. Within the 50 minutes of teaching time, 5-10 minutes is generally lost to students and instructor getting settled, course administration, and lecture review and lecture wrap up. What this means is that for every lecture session 15-20 minutes of lecture hall time is wasted.

While learning outcomes are important, lecture hall time is a limited resource. Students generally do not like early morning classes or classes on Fridays. Faculty often do not like evening classes. To split a 45 minute content lecture into three 15 minute content lectures would increase demands on the lecture hall time by 50% (1 hour to 1.5 hours). There just isn't that type of capacity. Splitting a 75 minute content lecture into five 15 minute content lectures is even worse (1.5 hours of lecture hall compared to 2.5 hours).

Using really short lectures would also likely cause a faculty uprising. At research universities (and all universities) teaching is only one aspect of the job. Teaching once a week for 3 hours is much more efficient than teaching ten times for 30 minutes.

Any inefficiencies in student learning can be offset by the students spending more time reviewing material.

  • Language classes at my university are 50 minutes, but also occur every day of the week. Commented Nov 16, 2016 at 21:41
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    I highly disagree with most arguments in this post, especially the last sentence, which emphasizes the student should correct the lack of effectiveness of long lectures by studying even more. Commented Nov 16, 2016 at 22:53
  • @QuantumBrick when you say you disagree, are you saying that lecture hall time is not limited (or that many short lectures would not use more lecture hall time) or are you simply upset about the practical limitations that universities are faced with?
    – StrongBad
    Commented Nov 16, 2016 at 23:04
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    I disagree because I don't see any limitations. I'm not talking about a teacher that has two 2-hour reservations for a classroom to try to spread them in 240 lectures one minute each. I'm talking about that guy understanding that using those 2 hours will be pointless. Self organisation should be the key: research shows you should not give long lectures, specially without breaks. Why do people still do it? Organise yourself such that you can lecture for a maximum of 75 minutes and the stop using that extra time. It won't help - actually, it will inflict damage. Commented Nov 17, 2016 at 11:51

I only have experience with the USA. Here, it depends on both the course and the weekly schedule. The most common two time patterns for a "normal" course, in my experience, are three lectures a week of (nominally) one hour each, and two lectures a week of (nominally) an hour and a half each. As others have said, the actual time will be five to ten minutes shorter, so that students have time to get from one lecture hall to the next one.

Many, but by no means all, professors will give the class a short break in the middle of the hour-and-a-half lectures.

Sometimes you'll have a course that meets only one day a week but for three to five hours; those are usually not lectures, though, but either "seminars" (small-group intensive discussion) or labs.


I've studied in 2 places in Europe and one in the US and the shortest lectures were 1hr 15mins, which again in my opinion is too much. Like yourself I also can't pay attention for so long. What is more, a lot of the material shown in a lecture that lasts more than an hour is unnecessary. Sometimes I feel that lecturers may even struggle to fill in so much time with meaningful material (at least in business) - there are only so many facts that students need to hear from you, which is why I avoid teaching responsibilities.

As a student I didn't even see the point in attending lectures - why be there so that someone reads to me off slides, when I can do that myself whenever and wherever I feel comfortable?

Your question is interesting - perhaps you can conduct a study about that? :) I would add that perhaps on-demand online lectures are an even better solution than shortening the lecture time.

Just my €0.02.

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    I also never really understood why would people bother going to classes until I met some very, very good teachers. They'd still keep talking for 2 hours, but even though I didn't absorb everything, going to the classes really made a difference. I also think online lectures are way, way better: I've been watching an online course and even though the guy talks for 2 hours I split the class along 3 days and have a delightful 40 minute lecture just for myself. Commented Nov 16, 2016 at 15:05

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