We ran battery tests on 17 phones – this model lasted the longest

Follow ZDNET: Add us as a preferred source on Google.

Out of all our tech devices, it's safe to say we use our phones the most. By extension, its battery life is one of the most important factors when considering which phone to buy or upgrade to. So which phone has the best?

To find out which smartphone battery reigns supreme, ZDNET tested 17 phones from six brands including Apple, Samsung, and Google, in two testing methods. The one phone that stood out above the rest in all our battery-life testing was the OnePlus 15, which is why it gets the ZDNET Lab Awards badge. 

Another phone that impressed us was the iPhone 17 Pro Max, which tied with the OnePlus 15 in general usage testing. Here's the full break down of our findings and how we regularly test smartphones. 

How we tested the smartphones 

Our two testing methods focused on measuring battery life after video playback and during general use. For the video playback testing (Figure 1), we left a three-hour YouTube video on and tracked the battery percentage over one, two, and three hours. 

Phone screen brightness was set to 100%, and auto-brightness and dimming were disabled. In addition, we used Wi-Fi only, notifications were turned off, volume was set to 50%, and the highest refresh rate was turned on.

Test 1: Video playback over three hours

Our general usage testing consisted of 30 minutes of using a smartphone for general use cases, including 10 minutes of social media browsing (Instagram and Reddit), 10 minutes of gaming (Asphalt 9), and 10 minutes of video calling (Google Meet on iOS and Android for consistency). Battery life was then tracked after these 30 minutes. 

To get an idea of a specific brand's general battery life, we averaged the general usage numbers for each phone in a brand to get the data in the graph below (Figure 2).

Test 2: General usage over 30 minutes 

ZDNET's editor-in-chief and smartphone expert, Kerry Wan, said there were some variables to consider in his testing, such as peak brightness levels (which hover around 2,000 nits), refresh rates (60 to 120Hz), and battery size. 

"One interesting point is that the OnePlus 15 is the only phone that we tested at the lab with a silicon-carbon battery, allowing it to store a higher capacity in a casing that's similar to conventional Lithium-ion batteries," Wan said. 

The results

The OnePlus 15 came out as the winner in both of our testing methods, with the highest battery life percentage after one (98%), two (94%), and three hours (89%) of running video playback. 

Read the review: OnePlus 15

For general usage, the OnePlus 15 had a battery life of 98%. Notably, the iPhone 17 Pro Max tied with the OnePlus 15 in general usage testing. 

In general, we found the three phones in Apple's iPhone 17 lineup to have the second-highest battery life averages (97.3%), running close behind OnePlus' 97.5% average, although those are the only two OnePlus phones we tested. 

Wan said it's no shock that Apple's latest iPhones have impressive battery lives, thanks to a few key updates.

"Having reviewed the latest iPhones, I've always found them to have the best standby battery, thanks in part to Apple's aggressive approach to memory and background tasks management," he said, adding, "Pair that with the largest battery capacity found on an iPhone, and you've got the 17 Pro Max model dropping the least percentage within the 30-minute general usage test."

As you can see from the spec chart above, not all smartphones did well in our testing. The Motorola Razr scored the lowest battery percentage in the video playback testing, and the Google Pixel 10 Pro Fold didn't impress either. That's not to say these aren't good phones, but that compared to other models on the market, their batteries aren't as capable. 

Your experience with a phone's battery, of course, might differ from our testing, depending on what apps you use the most (Facebook, Instagram, and Snapchat are all battery-draining apps ), your charging habits, if you use dark mode vs. light mode, wireless features running in the background, and more. 

But if you're looking to upgrade your phone this year, be sure to check our testing results before making your decision to ensure your new phone has a solid battery life. 

What is the best phone you can buy right now?

Our top pick for the best smartphone overall is the Samsung Galaxy S25 Ultra thanks to its thanks to its immersive and vibrant display, reliable battery life, and wealth of special features, some of which are powered by the company's latest generative artificial intelligence (AI) model.

Also: The best Samsung phones to buy in 2026

In our testing, the Samsung Galaxy S25 Ultra came in fourth place for video playback out of the 17 phones tested. It has a general usage battery life of 96%, which is on par with the other brand's flagship models.

How long should a phone battery last?

The average phone battery lasts about 22 hours on a full charge, which is great for staying connected on commutes, work flights, and evenings at home. But that's just the average. Actual use time varies by phone model, battery capacity, the power efficiency of its processor, and what you're using your phone for.

Featured reviews