The iPhone 17 models have much longer battery life than the iPhone 16 models, with the exception of the iPhone Air because there's no comparable ‌iPhone 16‌ model. Battery life is up six hours for most devices, with the ‌iPhone 17‌ seeing the most significant increase.

Streaming video can be played for longer, and the ‌iPhone 17‌ models support longer video performance, according to year-over-year comparisons of ‌iPhone 16‌ battery life and ‌iPhone 17‌ battery life listings provided by Apple.

• iPhone 17 - 30 hours video playback, 27 hours streaming video playback.
• iPhone Air - 27 hours video playback, 22 hours streaming video playback.
• iPhone 17 Pro - 33 hours video playback, 30 hours streaming video playback.
• iPhone 17 Pro Max - 39 hours video playback, 35 hours streaming video playback.
• iPhone 16 - 22 hours video playback, 18 hours streaming video, 80 hours audio.
• iPhone 16 Plus - 27 hours video playback, 24 hours streaming video.
• iPhone 16 Pro - 27 hours video playback, 22 hours streaming video.
• iPhone 16 Pro Max - 33 hours video playback, 29 hours streaming video.

The ‌iPhone 17‌ lasts for an impressive eight hours longer than the ‌iPhone 16‌ for video playback, and nine hours longer for streaming video.

Battery life will vary depending on device usage, which is why Apple uses "up to" in all of its battery descriptions. You may see longer or shorter battery life based on how you use your ‌iPhone‌, because most people aren't often watching video for 39 hours in a row.

Source: Macrumors