# "Academic time": why is 110 minutes called two hours?

I found an exam online from the MIT that states:

You have two hours (academic time, 110 minutes) to complete the exam.

What is this academic time unit and where does it come from?

• Comments are not for extended discussion; this conversation has been moved to chat. Apr 10 '18 at 10:31

The 10 minute interval given here seems to be common in the US, while in Europe 15 minutes is also in widespread use, but some universities also use 5 minutes.

It is to solve a rather practical scheduling problem: If one lecture ends on the hour sharp, and the next begins on the hour, you would have only zero time to walk an often non-zero distance to get to your next lesson/lecture/exam/whatever, requiring asymptotically infinite velocity to cover that distance - a theoretical and practical impossibility.

In order to solve this, European universities invented the so called "academic quarter", which is in use at some universities until today. It means that events start 15 minutes after their scheduled time.

The abbreviations c.t. (for cum tempore, en. "with time"), which means 15 minutes after the scheduled time and s.t. (sine tempore, en. "without time") which means exactly at the scheduled time stem from this. In some European universities (especially german), times are assumed to be c.t. unless stated otherwise.

Berkeley calls this 10-minute interval "Berkeley time", and MIT seems to prefer "academic time", although I have never seen it been used with intervals, only with instants in time so far.

There are many variations of this scheme, and many universities have their custom practices. Some start at the hour sharp and end five/ten/fifteen minutes early, some start five/ten/fifteen minutes after the hour and end sharp, and at some universites lectures both start five/ten/fifteen minutes late and end five/ten/fifteen minutes early, and maybe some universities use even other schemes (a comment refers to seven past the hour).
At my university, the academic quarter is used both at the start and end, since our campus is rather large and for some locations, you actually need almost 30 minutes when walking, and 20 when talking public transport in between those locations.

From personal experience, universities tend to move away from using c.t. times, and rather list actual (s.t.) start times on official resources/documents (e.g. 10:15 as start for a lecture), while students and professors would still refer to those lectures by their time slot (in this case 10 o'clock lecture) and make use of whatever length their university uses as "academic quarter" in colloquial speech.

At some universities, the academic quarter is also used as the time students have to wait for the lecturer. If the lecturer is late, but does not arrive within the academic quarter without any more information, students may assume the lecture is cancelled and can leave without the fear of missing any material.
(I recommend not leaving without being sure this is policy at your own university as well)

• Europe's a big place. Ten minutes is the norm at the British universities I've worked at. Apr 7 '18 at 23:39
• Why the &\$%! don't they just list the actual start time of the various classes and events? Apr 8 '18 at 1:42
• In the US, I'd be more used to classes etc. starting at the scheduled time and ending early. So a session that starts at 10 AM and covers two hours academic time would end at 11:50. Frank's answer indicates that other combinations of starting late and ending early are also used. It might be worth updating the answer to mention those possibilities. Apr 8 '18 at 3:12
• in Europe 15 minutes is widely used in many countries citation needed.
– user9646
Apr 8 '18 at 7:12
• @DanielSank Because it's easier to just say "ten o'clock lecture" than "five-past-ten lecture". Apr 8 '18 at 9:20

Classes begin five minutes after and end five minutes before the scheduled hour or half-hour.

Hence a "two-hour" lecture/exam lasts 110 minutes at MIT.

It is a scheduling problem. If you schedule two lectures directly after one another, then you need to add some time for the students to walk from one lecture hall to the next. So an "academic hour" is less than an actual hour, to allow for that.

• Of course, they could just start each successive class 10 minutes later instead, but this gets weird. Apr 7 '18 at 21:02
• In Queens University Belfast, our classes start and end 5 minutes before the hour to allow for this. Giving us 10 minutes between classes to walk to the different building on campus. Apr 9 '18 at 9:13

At many colleges, "1-hour" classes are 50 minutes long to provide 10 minutes of break time between classes. For example, a 2-hour class starting at 10:30am would end at 12:20pm, which is 110 minutes long.

• My classes in Trinity College, University of Dublin, follow that scheme, but a two-hour class has a ten-minute break in the middle (and a three-hour class has two breaks). And we still end ten minutes early.
– TRiG
Apr 8 '18 at 14:52
• Likwise, U of Toronto starts all classes at 10 minutes after the nominal posted start time. An older way of saying the same thing was to announce a meeting "at 2:00 pm for 2:10" or sometimes "come at 7:00 for 7:30"; in the latter case, the half-hour window for arriving could be used for socializing or finding a good seat, but the business of the meeting was expected to start sharply at 7:30, with no concessions to latecomers.
– CCTO
Apr 9 '18 at 19:37