The nine-minute snooze exists because of a physical gear inside the first snooze alarm clock. In 1956, General Electric-Telechron released the “Snooz-Alarm,” and the size and shape of its internal alarm gear made a nine-minute interval the only option that worked mechanically. Ten minutes wasn’t possible with the gear configuration, so nine became the default. Every clock and phone manufacturer since has simply kept it.
The 1956 Clock That Set the Standard
General Electric-Telechron designed the Snooz-Alarm as a futuristic bedside clock with a new feature: a button that would silence the alarm temporarily and re-trigger it a few minutes later. The engineering challenge was fitting this repeat function into the existing mechanical gear system. Clock gears operate on fixed tooth counts and ratios, and when GE’s engineers worked out the snooze mechanism, nine minutes was the interval the hardware could reliably produce. A clean 10-minute delay would have required a different gear configuration that didn’t fit the clock’s design.
Three years later, in 1959, Westclox introduced its own version called the “drowse” alarm, one of the first electrically powered models with a snooze function. By that point, nine minutes was already becoming the expected interval. As digital clocks replaced mechanical ones in the following decades, manufacturers had no technical reason to stick with nine minutes. They could have chosen any number. But nine minutes had become what consumers associated with snoozing, so it stayed.
Why Smartphones Still Default to 9 Minutes
Apple’s iPhone has used a nine-minute snooze since its first alarm app, and for years it wasn’t even adjustable. The choice was purely tradition. There’s no sleep science or user research behind it. Digital devices can set any interval down to the second, but Apple, Samsung, and other manufacturers carried forward the convention from mechanical clocks because that’s what people expected a “snooze” to mean.
Apple finally added customizable snooze durations with iOS 26 in 2025, letting users pick their own interval. The default remains nine minutes, but you can now change it. Most Android phones have offered adjustable snooze times for longer, though their defaults also tend to hover around nine or ten minutes.
What Happens to Your Sleep in Those 9 Minutes
Nine minutes turns out to be an awkward duration from a sleep perspective. It’s long enough for your brain to start drifting back into light sleep but too short to get any restorative rest. A sleep lab study published in the Journal of Physiological Anthropology found that using a snooze alarm in the final 20 minutes before waking shifted the brain away from stable, deeper sleep stages and into a pattern of repeated light drowsiness (called stage N1 sleep) interrupted by forced awakenings.
The numbers were striking. Participants using a snooze alarm experienced an average of 12.2 sleep-stage transitions in those last 20 minutes, compared to just 3.5 transitions when sleeping through to a single alarm. They were aroused from sleep about four times on snooze nights versus less than once on non-snooze nights. Their total sleep in that final window dropped by four minutes, and sleep efficiency got measurably worse.
The real cost showed up after getting out of bed. Reaction times were slower on snooze mornings, and participants didn’t experience the alertness boost that the non-snooze group did. People who slept straight through to a single alarm reported feeling significantly more vigorous at every check-in for the next 30 minutes. The snooze group didn’t get that same lift. The researchers concluded that snooze alarms prolong sleep inertia, that groggy, foggy feeling after waking, precisely because they force the brain through repeated partial awakenings.
Separate research on REM sleep fragmentation adds another layer. When REM sleep (the phase associated with dreaming and emotional processing) gets interrupted by brief arousals, the brain loses its ability to dampen physiological reactions to emotional experiences from the previous day. In other words, fragmented morning sleep may leave you more emotionally reactive, not just groggy.
If You’re Going to Snooze, How Long Should It Be?
For people who snooze habitually and aren’t severely sleep-deprived, sleep researchers suggest that the total snooze window should be 20 to 30 minutes. That’s enough time for the brain to work through sleep inertia, which typically lasts under 30 minutes in well-rested people. In practice, that means hitting snooze three or four times at five- to ten-minute intervals, or setting your first alarm 20 to 30 minutes before you actually need to be up.
Going beyond 30 minutes creates a different problem. Longer snooze periods let the brain sink into deeper sleep stages, which makes waking up even harder. And if you regularly feel unable to wake up after 30 minutes of snoozing, that’s a signal of sleep deprivation rather than normal grogginess. The snooze button, regardless of whether it’s set to nine minutes or any other interval, can’t substitute for sufficient sleep the night before.