Samsung Galaxy S24 Ultra battery life tested — this blows away iPhone 15 Pro Max

Samsung Galaxy S24 Ultra in hand showing display and home screen
(Image credit: Future)

The Samsung Galaxy S24 Ultra may have the same 5,000 mAh battery as the Galaxy S23 Ultra, but it lasts a lot longer on a charge. In fact, its endurance blows away the iPhone 15 Pro Max, which is already one of the longest lasting phones around. 

At Tom's Guide we test every smart phone using our own battery test, which surfs the web over a 5G connection at 150 nits of screen brightness. The handsets that make our best phone battery life list generally last 12 hours or longer on a charge. But the Samsung S24 Ultra sets the standard for flagships (at least beyond gaming phones). 

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Galaxy S24 Ultra Battery Test Results
PhoneChipsetBattery sizeBattery life (Hrs:Mins)
Samsung Galaxy S24 Ultra Snapdragon 8 Gen 35,000 mAh 16:45
Asus ROG Phone 8Snapdragon 8 Gen 35,500 mAh 18:48
Google Pixel 8 ProTensor G35,050 mAh10:03
iPhone 15 ProA17 Pro3,274 mAh10:53
iPhone 15 Pro MaxA17 Pro4,422 mAh14:02
Samsung Galaxy S23 UltraSnapdragon 8 Gen 2 for Galaxy5,000 mAh12:22 (adaptive) / 13:09 (60Hz)

In our first round of testing, the Galaxy S24 Ultra lasted an epic 16 hours and 45 minutes with its display set in adaptive mode (which means it can scale from 1 to 120Hz dynamically). That runtime is more than 4 hours longer than the Galaxy S23 Ultra, which lasted for 12:22 in our testing.

The S23 Ultra can go for as long as 13:09 if you put the screen in 60Hz mode, so long as you're willing to live with a less smooth display for that extra staying power. We'll be testing the S24 Ultra in 60Hz mode as well. 

The iPhone 15 Pro Max hit 14:02 in the Tom's Guide battery test. That's great, but it's still nearly 3 hours short of the S24 Ultra. Meanwhile, the Pixel 8 Pro conked out at 10:03, which is more than 6 hours behind Samsung's latest big-screen beast. 

Is the Samsung Galaxy S24 Ultra the longest lasting phone overall? Not quite, as that honor goes to the Asus ROG Phone 8, which is a gaming phone that uses the same Snapdragon 8 Gen 3 chip as Samsung's latest device. 

The new chip could help explain the very big battery life difference in juice between the Samsung Galaxy S24 Ultra and Galaxy S23 Ultra. After all, Qualcomm promises 25% better efficiency for the Snapdragon 8 Gen 3 vs the Snapdragon 8 Gen 2. But now that we're seeing the results, they're absolutely bonkers.

There's more good news. Using a 45W USB-C charger, the Galaxy S24 Ultra reached a 71% charge in 30 minutes, compared to 41% with a 20W Apple charger. 

Overall, the Samsung Galaxy S24 Ultra is one of the longest lasting phones ever. See our Galaxy S24 Ultra hadns-on review for more of our pros and cons about the new device. 

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Mark Spoonauer

Mark Spoonauer is the global editor in chief of Tom's Guide and has covered technology for over 20 years. In addition to overseeing the direction of Tom's Guide, Mark specializes in covering all things mobile, having reviewed dozens of smartphones and other gadgets. He has spoken at key industry events and appears regularly on TV to discuss the latest trends, including Cheddar, Fox Business and other outlets. Mark was previously editor in chief of Laptop Mag, and his work has appeared in Wired, Popular Science and Inc. Follow him on Twitter at @mspoonauer.