If you're trying to decide which iPhone 12 to buy, battery life should be high on your list. We put all of the new iPhone 12 models through our battery tests with mixed results.

The iPhone 12 mini was the smallest, had the smallest battery to match, and had the shortest 5G runtime. iPhone 12 and iPhone 12 Pro lasted longer, but fell a step short of competing Android phones.

According to our tests, the iPhone 12 Pro Max is the one to get if you want the longest durability, and it performed well against Android phones. It didn't quite break the 11-hour mark that ranks on our best smartphone battery life list, but it's close.

Here's how Tom's Guide's battery test works. We ran this test on the iPhone 12 and iPhone 12 Pro with 5G and 4G, and the difference was quite dramatic.

While not the only factor, the battery size for each model is listed below. iPhone 12 and iPhone 12 Pro battery sizes are based on certification and teardown, as Apple does not list battery capacity as part of the specs.

The iPhone 12 mini's battery is small at 2,227 mAh, so it is not a big surprise that this model lasted only 7 hours and 28 minutes on a web surfing battery at 5G. iPhone SE 2020, with an even smaller 1,821 mAh battery, lasted 9 hours 18 minutes, which lasted considerably longer. However, this test was conducted on 4G, which consumes less power.

The regular iPhone 12 lasted only 8 hours and 25 minutes on AT&T's 5G network. Last year's iPhone 11 lasted an impressive 11 hours and 16 minutes on 4G. For comparison, the iPhone 12 was switched to 4G only and lasted 10 hours and 23 minutes.

Samsung Galaxy phones generally last longer on 5G, although they lose more power when the screen is set to the faster 120 Hz refresh rate. For example, the Samsung Galaxy S20 took 9 minutes 31 seconds at 5G, but dropped to 8 minutes 04 seconds at 120Hz.

Google's Pixel 5 was nearly an hour better than the iPhone 12 at 9:56, but dropped to 9:29 when the screen was set to the faster 90 Hz refresh rate. Both times were well above the iPhone 12's 8:25 at 5G.

The iPhone 12 Pro fared a bit better, lasting 9 hours and 6 minutes on T-Mobile's 5G network. 4G run times jumped to 11 minutes and 24 seconds. iPhone 11 Pro was 10 minutes and 24 seconds on 4G.

The similarly priced Samsung Galaxy S20 Plus lasted 10:31 on 5G, nearly 1.5 hours longer than the iPhone 12 Pro. The Samsung phone's runtime drops to 8:55 at 120Hz, which is slightly worse than the iPhone 12 Pro at 5G.

To be fair, the Galaxy S20 Plus has a larger 4,500 mAh battery, while the iPhone 12 Pro's battery rating is 2,815 mAh.

Now we're talking: the iPhone 12 Pro Max's 3,687 mAh battery lasted a very impressive 10 hours 53 minutes at 5G. This is nearly two hours ahead of the iPhone 12 Pro. The Galaxy S20 Ultra with the much larger 5,000 mAh battery lasted 12 hours and 3 minutes, dropping to 9:13 in 120 Hz display mode.

Of course, the web surfing test is only one way to measure battery life; no one surfs the web for 10 or 11 hours straight. But the test does give us a way to compare endurance across multiple phones, even if it is a loaded test.

When not surfing the web, the iPhone 12's Smart Data mode automatically switches to 4G to help conserve battery power. However, this only works in certain scenarios, such as when streaming music with the screen off.

Overall, the battery life of the iPhone 12 and iPhone 12 Pro drops off a gaggle at 5G, at least when surfing the web. Therefore, it may be better to manually switch to 4G in some cases to conserve extra power.