Galaxy S21 Ultra 5G battery life: the longest lasting Samsung flagship?

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The Samsung Galaxy S21 Ultra is the most premium phone in the S21 series, and it's also the one that comes with the biggest battery.

Equipped with a massive, 5,000mAh battery, and benefitting from the latest and most power efficient, 5nm chips, as well as dynamic refresh rate screen, the S21 Ultra goes above and beyond in terms of battery life.

So how long will the S21 Ultra battery last users in the real world?

Galaxy S21 Ultra Battery Life


In real world use, we were getting north of 7 hours of screen time on the S21 Ultra, which is a great score and actually a bit more impressive than rivals like the iPhone 12 Pro Max, but to confirm that and see the details, we turn to our battery tests!

Web Browsing Test (Wi-Fi, 200 nits brightness)


Browsing test 60Hz (hours) Higher is better
Samsung Galaxy S21 Ultra 16h 7 min
Samsung Galaxy S21 9h 6 min
Samsung Galaxy Note 20 Ultra 11h 57 min
Apple iPhone 12 Pro Max 14h 6 min
Google Pixel 5 12h 40 min
Browsing test 120Hz (hours) Higher is better
Samsung Galaxy S21 Ultra 14h 43 min
Samsung Galaxy S21 7h 47 min
Samsung Galaxy Note 20 Ultra 9h 33 min

On our lightest test, web browsing, the S21 Ultra outlasted other flagships by a huge margin, and it scored impressively well even when it was running at the 120Hz Adaptive rate. We definitely recommend that smoother and more pleasing 120Hz mode, especially with such great battery life, but if you switch to 60Hz, you will indeed squeeze a bit more on this test. At 60Hz the S21 Ultra scored more than 16 hours, an all-time record for flagships!

YouTube Test


YouTube video streaming (hours) Higher is better
Samsung Galaxy S21 Ultra 8h 52 min
Samsung Galaxy S21 7h 36 min
Samsung Galaxy Note 20 Ultra 7h
Apple iPhone 12 Pro Max 8h 37 min
Google Pixel 5 8h 49 min


On our second test, streaming YouTube videos from the same playlist at the same, 1080p quality, the S21 Ultra once again shows it can last. It's not quite as far ahead in this test, and we would say that it lasts roughly as long as the iPhone 12 Pro Max and the Pixel 5.

3D Gaming Test


3D Gaming 60Hz (hours) Higher is better
Samsung Galaxy S21 Ultra 8h 40 min
Samsung Galaxy S21 7h 9 min
Samsung Galaxy Note 20 Ultra 7h 17 min
Apple iPhone 12 Pro Max 8h 1 min
Google Pixel 5 6h 51 min
3D Gaming 120Hz (hours) Higher is better
Samsung Galaxy S21 Ultra 5h 3 min
Samsung Galaxy S21 4h 14 min
Samsung Galaxy Note 20 Ultra 5h 9 min


Last but not least, we have our gaming test, and if you enjoy games like Call of Duty, PubG and Minecraft, look closer, this is the test you should care about. While the other two tests strain the CPU, this one pushes the GPU to the max and shows how effective it is.

And once again, the Galaxy outlasts rivals by quite the margin. Notice, however, that running this same test at 120Hz with compatible games like Minecraft, they do drain a lot more of the battery, so if you want a balance between performance and battery life, it really makes sense to game at 60Hz.

And here is how the battery sizes compare for all Galaxy S21 series phones, and a few other recent Galaxies:

  • Galaxy S21 Ultra battery: 5,000mAh
  • Galaxy S21 Plus battery: 4,800mAh
  • Galaxy S21 battery: 4,000mAh
  • Galaxy S20 Ultra battery: 5,000mAh
  • Galaxy S20 Plus battery: 4,500mAh
  • Galaxy S20 battery: 4,000mAh
  • Galaxy Note 20 Ultra battery: 4,500mAh

S21 Ultra Charging Speeds


The biggest news about the S21 Ultra and charging are probably that you won't even get a charger in the box. Following Apple which set the charger-less tone with the iPhone 12 series, Samsung has quickly decided to follow and removes the charger from all S21 series phones (you still get a standard USB to USB-C cable at least). 

So what charger is the best charger for the S21 Ultra? The phone supports up to 25W charging speeds (disappointing, considering last year's model could charge at up to 45W). With no charger in the box, most people would probably still be best off with the compact and affordable 25W Samsung fast charger sold for $35 (but currently discounted for $23 at Best Buy). We tested the phone with this charger and a full top-up takes around an hour and a half. With other phones by OnePlus and Xiaomi being able to fully charge their flagships in around 40 minutes, this looks really slow.


Of course, the Galaxy S21 Ultra also supports wireless charging, and Samsung is introducing a couple of new wireless charging to go with it. Maximum supported wireless charging speeds are 15W, and we recommend getting a Samsung-made charger that supports this maximum speed for faster top-ups.

All Galaxy S21 phones, including the Ultra, also support reverse wireless charging, or as Samsung calls it Wireless PowerShare. You can enable the feature from the drop down menu and once turned on, it transforms your phone into a kind of a wireless power bank, so you can place your Galaxy Buds or Galaxy Watch on the back of the phone and it will charge them up.

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