Better Battery Life on the New Apple Watch? Read the Fine Print
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This week, Apple introduced new Apple Watch models, as it has done every September for the past 11 years. However, this year was a bit different — in a few interesting ways.
For one thing, we got not one or two, but three new Apple Watch models. Apple updated the Apple Watch Series, Apple Watch Ultra, and Apple Watch SE, a trifecta we’ve seen only once before, in 2022 when the first Ultra appeared.
Still, this week’s announcement was interesting in that most of what Apple showcased for its new Apple Watch lineup isn’t actually exclusive to the 2025 models. That’s especially true for the health features: hypertension notifications will also be available on the Series 9, Series 10, and Ultra 2, while the Sleep Score is simply a mathematical calculation based on the sleep data in the Health app that doesn’t require an Apple Watch, much less a recent model.
The Apple Watch Ultra 3 and Apple Watch SE 3 were more significant updates as they came after a two- and three-year gap, respectively. However, the Apple Watch Series 11 differs from its predecessor in only three specific areas:
- 5G capabilities
- Increased durability with new Ion-X glass
- Longer battery life with (slightly) faster charging.
Even the colors haven’t changed significantly. Space gray replaces silver, but that’s a relatively subtle change compared to the green, blue, pink, and (PRODUCT)RED finishes of the Series 7–9 era.
In other words, if you’re already wearing an Apple Watch Series 10, there’s virtually no reason to upgrade to a Series 11. That’s not surprising, as Apple rarely offers massive year-over-year improvements, but these may be the most minimal we’ve ever seen. It didn’t even bother to give the chip a new name.
Still, if you’re someone who regularly pushes your Apple Watch battery to the limit, the promise of longer battery life might seem pretty appealing. For years, the Apple Watch has remained at a constant promise of 18 hours. That’s comfortable all-day battery life, but it can feel a little tight for those with an active lifestyle, especially if you also want to wear it to bed at night for sleep tracking.
By contrast, the Apple Watch Series 11 promises 24-hour battery life, and if that’s not enough, it also claims that you can get a full night of sleep tracking with only a five-minute charge. That’s three minutes less than the Series 7–10 models. The Apple Watch Ultra 3 gets a similar increase, moving from 36 hours to 42 hours, with the same five-minute sleep tracking charge promise.
While those are impressive gains, it seems this is a case where you’ll want to read the fine print, as Apple isn’t comparing the same types of fruit here to calculate its “all-day battery life.”
To set the standard for how many hours an Apple Watch lasts on a single charge, Apple measures the number of times you raise your wrist to check the time, how many notifications you receive each day, how many minutes you actively use apps, and how long you work out. However, for the Apple Watch Series 11, it’s added a new metric: Sleep Tracking.
Activities Each Day
Apple Watch Series 11
Apple Watch Series 10
Duration
24 hours
18 hours
Time Checks
300
300
Notifications
90
90
Minutes of app use
15
15
Workout (with Music Playback)
60 minutes
60 minutes
Cellular Use (if applicable)
4 out of 24 hours
4 out of 18 hours
Sleep Tracking
6 hours
N/A
Even though Apple added sleep tracking in 2020 with watchOS 7, it’s never factored this into its battery life calculation until now. As basic math reveals, 24 hours of battery life minus 6 hours of sleep tracking is still only 18 hours of daytime usage.
The numbers for low-power mode are similarly skewed. The Series 11 only gets a two-hour gain in this mode, but Apple’s tests also used lower levels of activity to achieve these results.
At the end of the day, there’s still an extra six hours here, but it’s six hours of extremely low-power use. While you’re sleeping with tracking enabled, your Apple Watch is sipping power, since even the always-on display is off, and the sensors are less active.
That’s not to say that the Apple Watch Series 11 doesn’t offer better battery life than the Series 10. The Series 11 is 1.4–1.6 grams heavier than the Series 10. Since not much else has changed, that increase is likely coming entirely from a larger battery cell inside.
As MacRumors points out, Apple’s regulatory filings confirm the batteries have increased by 7 to 10 percent overall, which is far less than the 33 percent gains implied by the new 24-hour battery life spec. Since the Series 11 otherwise contains the same hardware as the Series 10, there won’t be any power efficiency gains inherent in the new model. The new watchOS 26 update may offer some improvements, but those should be equally available to Series 10 owners.
In other words, you can probably cross extended battery life off your list of reasons to upgrade. The Apple Watch Series 11 and Ultra 3 will undoubtedly do better than their predecessors, but it’s unlikely to be as much of an improvement as the numbers suggest.
