Why does my video look right on my phone and wrong on my computer?

Because the phone is reading a rotation flag in the file and the computer's player is ignoring it. Turning the pixels removes the disagreement entirely.

Which way is 90 degrees?

Clockwise, as you look at the picture. If the top of your subject currently points to the left, that is the one you want.

Does rotating lose quality?

Turning the pixels means encoding the frames again, which costs a little. Writing the flag instead costs nothing, and the option is on the same page.

What about a small tilt, five or ten degrees?

No. Small arbitrary angles leave empty corners that have to be cropped or filled, which is a different job from a quarter turn.

Rotate Video

Turn a video the right way up, permanently.

Everything runs inside your browser. Your files never leave your device.

Drop your files here

.mp4, .m4v, .mov, .qt, .webm, .mkv, .ts, .mts, .m2ts · they stay on this device

Ask about Rotate Video

Questions about what this tool does, which option to pick, or what it can and cannot handle.

This is the one part of the site that uses a server. The question you type here is sent to an AI provider to be answered — your files and whatever you put in the tool above are not, and the assistant cannot see them. Answers are generated and can be wrong; the tool itself is not guessing.

About the Rotate Video

A video filmed on a phone held sideways is one of the most reliably annoying files in existence. It plays correctly in the app that recorded it, then arrives on a computer lying on its side, and everybody involved blames a different piece of software.

The explanation is that there are two ways a video can be rotated, and only one of them is a fact about the pictures. A phone records the frames in whatever orientation its sensor sits in and writes a small number in the file's header saying "display this turned ninety degrees". Players that read that number show it correctly. Players that ignore it — and plenty do, including a surprising number of upload forms, presentation packages and social platforms — show the frames as recorded, on their side.

So this tool offers both. Left switched on, it turns the pixels themselves: every frame is redrawn in its new orientation and the file no longer relies on anyone honouring a flag. That costs a re-encode and a little quality, and it works absolutely everywhere. Switched off, it writes the flag instead, which is instant, loses nothing at all, and works only where the flag is respected.

The default is to turn the pixels, because somebody arriving here has almost certainly already been let down by the flag. If your file is going straight into an editor that handles orientation properly, the cheap route is genuinely better and the switch is right there.

Ninety degrees clockwise, a hundred and eighty, and ninety anticlockwise are the three turns available. Anything else would need the frame padded out with blank corners, which is a compositing job rather than a rotation.

How to use it

1Add the sideways video — or several, if a whole shoot came out the same way.
2Choose which way to turn it.
3Leave "turn the pixels" on unless you know the next piece of software reads rotation flags properly.
4Rotate and download.

Questions

Why does my video look right on my phone and wrong on my computer?: Because the phone is reading a rotation flag in the file and the computer's player is ignoring it. Turning the pixels removes the disagreement entirely.
Which way is 90 degrees?: Clockwise, as you look at the picture. If the top of your subject currently points to the left, that is the one you want.
Does rotating lose quality?: Turning the pixels means encoding the frames again, which costs a little. Writing the flag instead costs nothing, and the option is on the same page.
What about a small tilt, five or ten degrees?: No. Small arbitrary angles leave empty corners that have to be cropped or filled, which is a different job from a quarter turn.