The main reason to use H.264 in 2026 is legacy device support. Some devices cannot play H.265, but H.264 is playable almost anywhere, as a 20+ year old codec.

I was surprised that Twitter only lets you upload H.264 still, in 2026.

For personal use, if those are your only two choices, then go with H.265 for higher efficiency, or H.264 for wider compatibility. If other codecs are an option, go with AV1 for higher efficiency. It’s currently the best and already pretty widely supported.

It depends on how you want to play or share the media.

E.g. I remember having lots of issues sharing smaller video files encoded with H.265 via both WhatsApp and Messenger. iMessage doesn't support H.265 (or at least it didn't work for me at the time).

Patents aside, h265 from my reading is almost universally better than h264. My understanding which could be wrong is that for a given quality h265 will always be smaller, and particularly for >1080p it's recommended. Hardware support has been around since at least the Shield days (2019) so that shouldn't be an issue. Only use h264 if you are needing to hw-decode on really old hardware.

AV1 is the future/present: Fully open standard, better than h265. Only downside is hardware support: You need hardware made in the last few years.

H.264 (if you want to support 20 year old devices) or av1. Don't use h.265. The patent situation around it is a total mess.

H.265 didn't play in the browser in old devices.

Newer browsers do play it. It's vastly superior in storage space and scalability to H.264, but you used to need to transcode H265 to H264 to play in browser without a plugin.

h264, if you had a reason to use something else you wouldn't need to ask

That all depends on your use case.

How are you generating video?

How are you playing it back?

H.264 for 1080p and less. H.265 for 2160p.

that's like asking "should I use an audi or a tesla"