You have seen the claim that every interruption costs you 23 minutes. It is not in any study. This tool shows you the arithmetic people do with the one real figure that exists, and then why even that total does not mean much.
How to read this
A message, a tap on the shoulder, a meeting that breaks your focus. Estimate for a normal day.
The arithmetic people usually do
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Why this number
This multiplies your number by the one measured figure that exists. In a field study of information workers, “when people did resume work on the same day, it took an average length of time of 25 min. 26 sec (sd=54 min. 48 sec.).” So the sum here is your interruptions times about 25.4 minutes. Read the next line before you trust it.
Why that total is close to meaningless
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Why this number
The standard deviation in that study was 54 minutes 48 seconds, more than twice the average. A spread that wide means the average describes almost no individual interruption, so multiplying it out gives a confident-looking total built on a figure that is anything but. The popular “23 minutes” version is worse still: it appears in no peer-reviewed paper at all.
What to take from this instead. Switching between tasks is not free, and the feeling of losing your place is real. But there is no reliable per-interruption cost to bill your day against, and the number most cited for it is invented. Use this as evidence that interruptions are worth reducing, not as a stopwatch on what they cost you.
Figure from Mark, Gonzalez and Harris (CHI 2005), “No Task Left Behind?”. Background: How Long Does It Take to Refocus After an Interruption?
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Read this before you trust the number
This tool is deliberately built to undercut itself. It exists to show that the confident “cost of an interruption” number people quote is not something the research supports. The “23 minutes 15 seconds” figure appears in no peer-reviewed paper at all.
The one measured average it uses carries a standard deviation more than twice its size, which means multiplying it out produces a tidy-looking total built on a figure that describes almost no individual interruption. Read the second result, not just the first.
Where the numbers come from, and do not
The only measured figure is from a 2005 field study of information workers, which reported an average resumption time of 25 minutes 26 seconds, with a standard deviation of 54 minutes 48 seconds. The popular 23-minute version cannot be traced to any published study. So this tool shows the honest average, alongside the spread that makes a daily total close to meaningless.
What to do instead
Switching between tasks is not free, and the feeling of losing your place is real. But there is no reliable per-interruption cost to bill your day against. Use the fact that interruptions add friction as a reason to reduce them, not as a stopwatch reading you can put in a report.
Common questions
Is the 23-minute refocus statistic real?
No. It does not appear in the paper it is almost always credited to, and we could not trace it to any published study. The nearest real figure is a 25 minute 26 second average, with an enormous standard deviation.
So interruptions do not cost anything?
They do have a cost; task switching is measurably not free. The point is that there is no trustworthy single number for it, so any confident daily total is more rhetoric than measurement.
Why show the total at all, then?
Because people reach for it anyway. Showing the arithmetic next to the spread that undoes it is more useful than pretending the number does not circulate.