How to rotate a sideways video
Almost always a fixable rotation flag, not broken footage. Here is how to fix it on each platform.
Why a video ends up sideways
A phone records video in whatever orientation it was held, then writes a rotation flag into the file telling players to display it upright. Most apps read that flag correctly; some players, older software and a few messaging apps ignore it and show the raw, sideways frame instead. Re-encoding the video with a real 90-degree turn, rather than relying on the flag, fixes it everywhere.
On an iPhone or iPad
Open the video in Photos, tap Edit, then use the crop tool: tap the rotate icon (a square with a curved arrow) at the bottom-left of the crop screen to turn it 90 degrees, tapping again for more, then Done. This saves a real rotation, not just a flag.
On Android
In Google Photos, open the video, tap Edit, open the crop/rotate tool, and tap the rotate icon until the video is upright, then save. Samsung Gallery's editor has the same rotate control.
On Windows
Clipchamp (preinstalled on Windows 11) has a rotate button on the clip once it is on the timeline: import the video, select it, and use the rotate control in the properties panel, then export.
On a Mac
QuickTime Player can do this directly: open the video and use Edit, Rotate Left or Rotate Right from the menu (or Cmd-R), then File, Export As, to save the corrected version.
When the fix does not stick
Some tools only change the rotation flag rather than the pixels, so the video looks right in one app and sideways again in another. Stayput's rotate video tool re-encodes the actual frames in your browser tab, so the fix holds everywhere the file is played, including sites and apps that ignore rotation metadata. It also flips a video horizontally for a mirrored recording. Nothing is uploaded: the rotation happens on your device.
Questions
Why does my video look fine on my phone but sideways when I send it?
Your phone's player reads the rotation flag correctly; the app or device you sent it to may not. Re-encoding the rotation into the actual frames fixes it everywhere.
Does rotating a video re-encode and lose quality?
Rotating by 90 or 180 degrees does not need to resample the image content, only reorder it, so a good encoder keeps quality very close to the original at a matching bitrate.
Can I flip a video like a mirror, not just rotate it?
Yes, a horizontal flip is a separate operation from rotation, useful for footage recorded in a mirror or by a front camera that came out reversed.
Will rotating fix a video that plays upside down?
Yes, a 180-degree rotation is the same fix, just turned twice as far.