I'm writing a web application in which you can make bookings. When configuring a booking I need to know for how long the session will be. I'm wondering if the best word is length or duration?

Length: [100 minutes]


Duration: [100 minutes]

Or is there perhaps a better alternative?


  • Duration is a better choice
    – mplungjan
    Oct 1, 2014 at 11:26
  • 3
    Duration is equivalent to length of time. So if you use "length", you only imply the time. In forms, or UI in general, it's usually a good idea to be as specific and explicit as possible, so duration is better.
    – oerkelens
    Oct 1, 2014 at 11:30
  • Duration. But make sure that everyone are clear on whether the time is total time or running time. Total time is the time from start to finish, the movie starts at 10:00 and ends at 11:45, so total time is 105 minutes. But the running time of the movie itself is 95 minutes, and 10 minutes was the intermission. Oct 1, 2014 at 11:49

3 Answers 3


Either word can be used in this context, and they'll be understood perfectly well. Duration is more specific to lengths of time, so it might be more appropriate. On the other hand, length is a more familiar word; using duration makes it seem more proper or technical.

  • 1
    I agree with your answer, except the part that duration sounds "snobbish". Unlike length, it also has the bonus of indicating that what is being measured is definitely time. Feb 18, 2021 at 15:48
  • 1
    Maybe "technical" would be a better description.
    – Barmar
    Feb 18, 2021 at 16:43
  • Yes, "technical" is better! I wanted to propose "accurate", but assuming your answer is correct, they are both accurate. And I didn't want to sound "snobbish". ;) ;) Feb 19, 2021 at 1:48
  • @RockPaperLz-MaskitorCasket Well, I'm trying to explain why it's not more common in casual conversation. Accuracy doesn't express that.
    – Barmar
    Feb 19, 2021 at 1:55

Although you didn't ask about it, the previous answer correctly notes that duration isn't used for distance; from en.wiktionary, duration means “An amount of time or a particular time interval” and “The time taken for the current situation to end, especially the current war”, plus a technical finance meaning (“A measure of the sensitivity of the price of a financial asset...”).

While you can use either of duration or length (see below), a shorter word you might consider is term. From en.wiktionary, sense 11 is “Duration of a set length”.

Besides length's primary sense “The measurement of distance along the longest dimension of an object”, en.wiktionary mentions senses “duration” and (figuratively) “Total extent”.


Opinion: Length be used to define distance or size ( length very commonly refers to physical size i.e., the length, width, and depth of an object) whereas duration measures time period.

Length is also used to define time period, as in: How long have you been waiting?

So, while length may be used for either, duration should not be used for distance.

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