Obviously the goal is for an application to load almost instantly but I am curious as to what the average time would be before users perceive an application or website as "too slow". So, I'm curious as to what is the threshold of user abandonment or the perception that the application is too slow?


2 Answers 2


Jakob Nielson describes the 3 time limits which he calls the 'Response-Time Limits':

There are 3 main time limits (which are determined by human perceptual abilities) to keep in mind when optimizing web and application performance

It is an article written in 1993, but three years ago he published a new research report on website response times stating that:

The 3 response-time limits are the same today as when I wrote about them in 1993 (based on 40-year-old research by human factors pioneers):

  • 0.1 seconds gives the feeling of instantaneous response — that is, the outcome feels like it was caused by the user, not the computer. This level of responsiveness is essential to support the feeling of direct manipulation (direct manipulation is one of the key GUI techniques to increase user engagement and control).
  • 1 second keeps the user's flow of thought seamless. Users can sense a delay, and thus know the computer is generating the outcome, but they still feel in control of the overall experience and that they're moving freely rather than waiting on the computer. This degree of responsiveness is needed for good navigation.
  • 10 seconds keeps the user's attention. From 1–10 seconds, users definitely feel at the mercy of the computer and wish it was faster, but they can handle it. After 10 seconds, they start thinking about other things, making it harder to get their brains back on track once the computer finally does respond.

A 10-second delay will often make users leave a site immediately. And even if they stay, it's harder for them to understand what's going on, making it less likely that they'll succeed in any difficult tasks.

For mobile applications and websites he further states that users are even more rushed because of the mobile setting. But he doesn't state whether that has any influence on the users perception of the speed of a website or application. So I can't say whether that is true or not.

Hope this answers your question.

  • I will dig deeper into Mobile Usability- I sometimes forget how great of a reference it is. Thank you for the response, it's what I was looking for.
    – Stephen
    Commented Apr 15, 2014 at 15:53
  • Np. There are some great articles on his website. Worth checking out every once in a while
    – GWv
    Commented Apr 16, 2014 at 5:56

I recall that 2 sec is when some start dropping out nowadays. Of course it depends on the site and the situation. Also it depends on the timing of separate parts of the site. For example, layout, text, and image placeholders might load earlier while images load later. Other stuff can happen in the background.

Perceived performance is more important than actual performance.

The user should see something within 0.2 sec. Even seeing the url being resolved after clicking a link is something. I'd say some part of the page should appear within 1 sec. The page should be fully loaded within 3 sec.

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