Why is the snooze bar on alarm clocks, set for 9 minutes?

Answer 1

It's the maximum delay you can get without doing any time calculation math which would drive up the cost of the parts. For instance, if you hit the bar and the last digit is 4, the alarm will trigger when the next 3 happens. It doesn't matter if its 14 -> 23, 44 -> 53, 54 -> 03, etc. If you tried to go longer, you'd have to know the hour rolled over for something like 54 -> 09 (15 min delay). Since it also comes close to what most people would want -- 10 minutes -- it solves everyone's problems with minimal cost.

So why not 10 minutes? You'd have to remember the trigger minute, 4, and make sure that you complete the present minute, also 4. This takes some additional logic in the clock parts over the 9 minute version. When the first digital clock parts were designed long ago, space on integrated circuits was expensive, so they went with the design that used the least space (9 minutes). Now, everyone is used to the 9 minutes, so they just don't bother to change it (most of the time).

Answer 2

I hate doing the math of what time I'd be getting up if I wanted to snooze X amount of times. It drives me nuts. It should be 10 minutes.

Answer 3

You need nine minutes because it takes one more minute to turn off the clock and then get out of the bed there making it a total of ten minutes, a nice round number.

Answer 4

Mine is 5 minutes. I guess 9 lets you get far enough back to sleep that the alarm is really annoying instead of just bothersome.