Apple Watch Series 9 battery life — this is how long it lasts

Apple September Event 2023
(Image credit: Apple | YouTube)

Now that Apple’s next smartwatch is official, you might be wondering about the Apple Watch Series 9 battery life. Historically, the Apple Watch hasn’t been considered the best smartwatch in terms of battery life, but there’s some updates over the years worth noting. 

For example, this year’s flagship now has a 100% recycled cobalt battery, helping the Apple Watch Series 9 become part of Apple’s first family of carbon neutral-certified products. This doesn’t have any impact on the battery performance, though the watch’s new S9 SiP does promise 25% improved power efficiency. 

While the performance boost is certainly welcome, it doesn’t mean the battery life of the Apple Watch Series 9 is any different from recent models. In fact, since the retina display’s brightness is boosted from 1,000 to 2,000 nits for this year’s watch, the S9 chip is tasked with offsetting the display’s higher power demand so it doesn’t hurt the battery's stamina.

Pretty much every flagship Apple Watch model has touted an 18-hour “all day” battery life, meaning with average use, your smartwatch should need to be charged once daily. Models from the Apple Watch Series 7 onward support fast-charging, bringing the device from dead to 80% in just 45 minutes, so your watch doesn’t need to spend too much time tethered to a charger.

In both respects (battery life and charging) the Apple Watch Series 9 is the same as the previous-gen Apple Watch Series 8. It even gets the Apple Watch low power mode that debuted alongside last year’s watch. Low power mode is available for all Apple Watch models running watchOS 9 or the newer watchOS 10 software, which arrives September 18.

The Apple Watch Series 9 will ship with watchOS 10, so low power mode will be ready to use. By disabling certain battery-draining features — ie. Always On Display, continuous heart rate monitoring — low power mode extends the smartwatch’s battery life up to 36 hours. So theoretically, if battery life is your priority, you could keep low power mode enabled to double the Apple Watch’s standard battery estimate. 

What about Apple Watch Ultra 2 battery life?

If battery life is a priority, you might want to consider the Apple Watch Ultra 2. Apple’s refreshed rugged sports watch has the same performance upgrades as the Apple Watch Series 9. It gets the U2 ultrawide-band chip and clever new double tap feature, too.

What’s more, one of the biggest differences between the Apple Watch Ultra 2 vs. Apple Watch Ultra is that the new watch display reaches 3,000 nits brightness compared to 2,000 nits on the original. Even with a brighter display, the Apple Watch Ultra 2 gets 36 hours of battery life with normal use.

With low power mode, the Apple Watch Ultra 2 gets up to 72 hours of battery, which is the best Apple Watch battery life possible.

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Kate Kozuch

Kate Kozuch is an editor at Tom’s Guide covering smartwatches, TVs and everything smart-home related. Kate also appears on Fox News to talk tech trends and runs the Tom's Guide TikTok account, which you should be following. When she’s not filming tech videos, you can find her on an exercise bike, mastering the NYT Crossword or channeling her inner celebrity chef.