When I have to load new information from my web server via ajax after a user action, how fast should the information be displayed for the user in order to be a good working UI for the user?


4 Answers 4


I've always been told that a delay of 100ms is generally not perceivable. An answer in a similar StackOverflow thread says:

The 100 ms threshold was established over 30 yrs ago. See:

Card, S. K., Robertson, G. G., and Mackinlay, J. D. (1991). The information visualizer: An information workspace. Proc. ACM CHI'91 Conf. (New Orleans, LA, 28 April-2 May), 181-188.

Miller, R. B. (1968). Response time in man-computer conversational transactions. Proc. AFIPS Fall Joint Computer Conference Vol. 33, 267-277.

Myers, B. A. (1985). The importance of percent-done progress indicators for computer-human interfaces. Proc. ACM CHI'85 Conf. (San Francisco, CA, 14-18 April), 11-17.

  • 6
    Good luck getting an AJAX operation done within 100ms. Commented Aug 10, 2010 at 6:07
  • Yeah, this is totally unrealistic unless you're performing really simple operations. I think this applies to other kind of interactions, e.g. the visual feedback when you type something.
    – Ignacio
    Commented Aug 11, 2010 at 16:56
  • 1
    it may be unrealistic to assume all operations happen that fast but that isn't the point. You only need to give feedback (e.g. show a loading image), something to tell the user their click did something. Best case: your app should be as fast as possible.
    – Samuel
    Commented Aug 12, 2010 at 12:13
  • 1
    @Samuel, that's cool, as soon as the user clicks the button, feedback must be sent out to the user (if the operation takes longer than 100ms). But the question here is how much time should the operation take when loading new information. So, the answer is: As little as possible. And to be more precise/realistic: Instantaneously, if not, less than 1s, if not, keep it under 10s.
    – Ignacio
    Commented Aug 12, 2010 at 18:07
  • Yea, this is a rather unrealistic objective to be considered the correct answer.
    – DA01
    Commented Apr 4, 2011 at 14:45

I guess this should follow the classic usability guidelines for response time.

  • 0.1 second is about the limit for having the user feel that the system is reacting instantaneously, meaning that no special feedback is necessary except to display the result.

  • 1.0 second is about the limit for the user's flow of thought to stay uninterrupted, even though the user will notice the delay. Normally, no special feedback is necessary during delays of more than 0.1 but less than 1.0 second, but the user does lose the feeling of operating directly on the data.

  • 10 seconds is about the limit for keeping the user's attention focused on the dialogue. For longer delays, users will want to perform other tasks while waiting for the computer to finish, so they should be given feedback indicating when the computer expects to be done. Feedback during the delay is especially important if the response time is likely to be highly variable, since users will then not know what to expect.

source: http://www.useit.com/papers/responsetime.html

  • 2
    10 sec seems like an awful lot when you are browsing.
    – Daniel O
    Commented Aug 9, 2010 at 19:57
  • 1
    It is. And that's why from 1 to 10 seconds the chances of the user getting distracted with another point of attention gets bigger. When it reaches 10 seconds it's almost certain that you've lost the user's attention.
    – Ignacio
    Commented Aug 9, 2010 at 20:05
  • So, 10 seconds is when you know you have total failure. I've seen a four second limit for page switches for some years now. Commented Aug 10, 2010 at 5:57
  • Also, it varies on the type of operation. If you're getting one field from DB and displaying it, it shouldn't be near 10s or even 4, that should be almost instantaneous and no feedback is needed (spinners, progress bar, etc) But I think this is a general rule, that applies to more complex and common operations.
    – Ignacio
    Commented Aug 11, 2010 at 15:39
  • I thought there would have been a lot more studies on response times. Hasn't google done a lot of this? What about the 2 Second Rule? usabilityfirst.com/glossary/2-second-rule .
    – Morgan T.
    Commented Nov 7, 2011 at 16:35

The information should load as fast as possible. the important thing is while they are waiting for the real action you should give them some "loading..." sign so the user knows that the action worked. It's really annoying to click a link and not see anything happen.


If the request is synchronous, it should take no longer than a couple of seconds, or the user will wonder what is wrong as the UI freezes. If you can use asynchronous requests, show a "loading" screen and progressively update the UI as soon as data come in, a longer loading time is probably okay.

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