Why You Can't Rely On Progress Bars

Progress bars. They're better than nothing, but who among us hasn't stared at a misleading, confusing or wholly inaccurate progress bars and wondered, "Why can't anyone make these more accurate?" Popular Mechanic's John Herrman answers that question.

Image remixed from CSS-Tricks.

The short answer: Many variables are involved in how long a process or download is going to take, and your computer isn't that good at calculating unknowns. Herrman's full post is an interesting read, but the main takeaway: Progress bars really are better than nothing (imagine an alternative where you wait for a result with no indication of progress until a process is complete), but you shouldn't set your watch by them (which you probably already knew).

Got a most-hated progress bar? Commiserate in the comments.

Why the Progress Bar Is Lying to You [Popular Mechanics]


    adobe cs5 suite was pretty mammoth

    battlefield 2 when calculating the shaders for the first time.

    Progress bars arent time related. They are processors related.
    Eg: when it shows 50% it means its completed 50% of the tasks for installation.
    WHen a progress bar sits on 99% that last percent just happens to take a lot longer than the previous 99%.
    Thats my argument to why they piss me off so much.

    As mentioned by warcroft, "progress" bars refer to how much of progress has been made, not how long it will take. (there are progress bars which will also give you an approximate time to complete, but they are always almost wrong)

    There's a difference between the progress bar (how much is done) and the "time to complete" estimation. Start a 5GB file transfer, then start another one from/to the same disks and see the effect. It's not rocket science!

    Interestingly, it's only in the latest versions of Windows (I think it started with Vista) that the file transfer progress bar was actually reliable even as an indicator of progress. Often the actual disk write operation would take place after the bar had finished and gone offscreen. This lead to plenty of accidents.

    These days I find "TeraCopy" has very reliable two-tone progress bars; and of course there's the venerable ProgressQuest ^__^

      Agreed. TeraCopy goes straight onto any new Windows install I do.
      That, and DeskPins.

    Installer progress bars that whip through from 0-100 in no time at all only to start over again several times. How many times nobody knows until it's finished - is that really better than nothing?

    I remember Valve's old HL engine progress bar was really annoying and inaccurate. Same thing went for the source engine.

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