Why does my iPhone 12 Pro Max get hot when I am watching video

Hi there,

From what we can tell, you're asking if it's normal for your iPhone to get warm when using it and watching videos. We're glad you've joined us in Apple Support Communities, and we can provide some guidance.

"When you use the device or charge the battery, the device might get warm. You might notice that your device feels warmer in these situations:

• When you set up your device the first time
• When you restore from a backup
• When apps reindex or reanalyze data, like Photos tagging for faces, places, or keywords after a software update
• When you use graphics-intensive or augmented-reality apps or features

These conditions are normal, and your device will return to a regular temperature when complete."

With that said, it's normal for your iPhone to get warm when watching videos, since that would be a graphics-intensive task. Have a look at this support article to learn more:

Keeping iPhone, iPad, and iPod touch within acceptable operating temperatures

If you've seen any temperature alerts appear on the screen of your iPhone, you'll want to be sure to follow the steps in the 'If you see a temperature warning screen' section of the link above.

Next, you mentioned the battery in your iPhone seems to be weaker than it was before, although the Maximum Capacity in Settings > Battery > Battery Health is 100%.

"“Battery life” is the amount of time a device runs before it needs to be recharged. “Battery lifespan” is the amount of time a battery lasts until it needs to be replaced. One factor affecting battery life and lifespan is the mix of things you do with your device. No matter how you use it, there are ways to help. A battery’s lifespan is related to its “chemical age,” which is more than just the passage of time. It includes different factors, such as the number of charge cycles and how it was cared for." Review the information in this link to learn more about your iPhone battery and how it affects performance:

iPhone Battery and Performance

Also, try the suggestions in the 'Tips for iPhone, iPad, and iPod touch' section of this link to help maximize battery life on your iPhone:

Maximizing Battery Life and Lifespan

We hope this provides some clarity about how using your iPhone affects the temperature and battery life.

Take care.