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Kevin Lynch details how Apple Watch keeps time, says 4x more accurate than iPhone

Screen Shot 2015-12-30 at 10.40.19 AM

One of the more curious ways Apple has marketed the Apple Watch from the start is as an “incredibly precise timepiece” that “keeps time to within 50 milliseconds of the definitive global time standard.” Macs and iPhones generally don’t have issues with keeping accurate time, and luxury watches actually do have a reputation for needing adjusting occasionally.

Now in a short discussion with Mashable, Apple’s Steve Jobs-approved VP of Technology Kevin Lynch has shared new details about how exactly all Apple Watches stay in perfect sync, even saying the method makes it four times better than the iPhone it relies on at timekeeping …

Lynch actually told us that “as a piece of hardware, [Apple Watch is] far more accurate as a timekeeping device than the iPhone,” said Lynch. It’s actually four times better, he noted.

“Through the whole stack, we’ve really paid attention to the accuracy,” Lynch said, adding that Apple actually tests that accuracy with high-speed cameras that watch, frame-by-frame, as the Apple Watch second hand moves around, watching closely for even a hint of latency.

Lynch also described the method Apple uses to keep the Apple Watch time as accurate as advertised:

“First of all, we’ve curated our own network time servers around the world,” said Lynch. There are, by his count, 15 such “Stratum One”-level Network Time Servers (NTP) (one level down from an atomic clock), scattered around the world. They’re all housed in buildings with GPS antennas on the roof that talk, you guessed it, to GPS satellites orbiting the earth, which all get their time information from the U.S. Naval Observatory. In other words, those satellites are all getting their times from one, big orbiting system.

Lynch added that latency with handoff between the iPhone and Apple Watch means there’s necessary corrections for time-delay in the process as well. You can read the full discussion at Mashable; it all sounds very impressive and typically Apple.

So long as the Apple Watch doesn’t get hit with any major time-related bugs like the one that made iPhones stuck in Do Not Disturb mode on New Year’s Day as Apple advertised that feature with Serena Williams, I’ll be satisfied with my Apple Watch’s timekeeping.

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  1. pretsky - 7 years ago


  2. chrisl84 - 7 years ago

    iOS 9 definitely had some kind of time keeping bug in it. My iPhone was around 100 seconds slow for some reason. 9.1 brought it back to correct time.

  3. cdm283813 - 7 years ago

    They need to figure out how to make this a must buy product. Telling me that the watch is 4x more accurate than my iPhone makes me second guess my iPhone 6s purchase; not make me run out and buy another Apple product.

  4. mpias3785 - 7 years ago

    I have a time app that connects to (THE US atomic clock near Fort Collins, CO, home of WWV and WWVB), why does Apple bother using its own time servers when that is available? I even have my Macs looking there. There should be a setting on the iPhone to select this on the iPhone.

    • jakexb - 7 years ago

      They say they “curated” a list. I bet NIST is on that list.

    • standardpull - 7 years ago

      Because the NIST NTP time servers aren’t designed to dole out time to millions of devices. Read up on NTP and you’ll learn quite a bit. There is an awesome tech website on the subject.

      Furthermore, GPS is better than any stratum 1 time server. And a stratum 2 server is very very accurate too.

  5. Pardon if I am misunderstanding something here, but the NTP servers have nothing to do with Apple. Those time servers are used in everything from computers, phones, and smartwatches to the printers in an office. Is he saying Apple has a separate 15?

  6. Rasmussen (@Twitboydk) - 7 years ago

    So what would then happen if the time wasn´t precise down to 50 miliseconds? It´s not like we would be late for a meeting. LOL. Who cares.

  7. Ashrakay (@Ashrakay) - 7 years ago

    We made the watch to fix the problems with our phone! It’s the ultimate peripheral device for people who need 5:00 to be 4x more accurate.

  8. yojimbo007 - 7 years ago

    I love my AppleWatch.. But does this really matter? Specially that i cant even perceive it🤔😳

  9. If the atomic clock time setting goes through the iPhone to Apple Watch via bluetooth to keep the watch 4x accurate, why not use the same data and make iPhone equally accurate? I mean its already in the phone before it gets to the watch. Makes no sense.

  10. vandiced - 7 years ago

    What the hell does this even mean? It’s a stupid computer with software based timing. If it were cogs and wheels and its timing was precise the now we are talking!

  11. charismatron - 7 years ago

    9to5 Mac: what is with this flurry of Apple Watch articles/ads? Honestly?

    • mpias3785 - 7 years ago

      Every site and blogger that has touted the Apple Watch as some great, innovative product is trying to spur sales so when Apple finally releases sales figures, they won’t turn out to be so disappointing. If initial sales were good, Apple would have announced that with the same glee they announce iPhone sales figures after the first weekend. The Apple Watch was a ludicrously overpriced, late-to-the-game, me-too device that left most Apple aficionados thinking “so what?”. They’re trying to do anything they can to save face.

  12. How can anyone perceive the difference? You have to worry when the VP of tech is talking excitedly about this, instead of looking at the device from a human point of view, he’s looking at it like a programmer.

    If the watch was made for sport, an ipod-garmain combo, it would be perfect. $100-300, GPS, heart rate, wireless headphone, all your music, podcasts, works standalone, sends the workout data to your mac and ios devices…etc. That would be hard to resist!

    • standardpull - 7 years ago

      You’re right. If you have a watch that’s only off by 50 ms, that’s very accurate.

      But the advanced idea hidden in his statement is apparent when you compare a “smart” watch to other timepieces that are not time-synched. With traditional watches, inaccuracies are summed up over time.

      After a few months, you’ll need to reset your watch because it is minutes off.

      Some quartz and mechanical watches are tuned and compensated for temperature, shock, friction and wear. They cost hundreds or thousands of dollars.

  13. waltertizzano - 7 years ago

    It might be precise to 50ms, but there is no way of seeing the time with that level of precision, since the digital face doesn’t have seconds (let alone milliseconds) :(

    • cdm283813 - 7 years ago

      Exactly! If this is their sales pitch someone needs to be fired! Tell me that you fixed some of the initial issues with the watch. Or maybe improve upon some of the basic functions. The average consumer could care less about 4x accuracy.

  14. mockery17 - 7 years ago

    What’s up with the people here completely failing to comprehend or even read the quote?

    “Lynch actually told us that ‘as a piece of hardware, [Apple Watch is] far more accurate as a timekeeping device than the iPhone,’ …”

    Lynch simply states that, on the hardware level, the Apple Watch is more accurate. Nowhere does it say Apple didn’t make it as accurate on the iPhone **using software tweaks**.

    The stupidity of the commenters here is just stunning.

  15. Gregg Palmer - 7 years ago

    Lynch should do all of apples product announcements…the guy is awesome

  16. Bradley Dichter - 5 years ago

    And how is the time keeping on a Mac? I changed the time server to so be safe.


Avatar for Zac Hall Zac Hall

Zac covers Apple news, hosts the 9to5Mac Happy Hour podcast, and created