The short answer
Open the video in the rotation tool below. Choose 90° right, 90° left or 180°, or step with the turn buttons until the preview looks right; the preview plays the video already turned and shows the size of the result. Keep Method on Fast (no quality loss) and press Rotate video. When it is done, a player with the result appears with a Download button.
The video stays in its original format (an MP4 stays MP4) and the sound is kept. Everything happens on your device, so nothing is uploaded.
Try it here: Rotate Video
Open the full tool pageWhy videos end up sideways
A phone camera sensor always records in the same direction. When you hold the phone upright, it does not turn the pictures; it writes an orientation setting into the file that tells players to show the video turned by 90 degrees. Most of the time this works perfectly.
Problems appear when the phone guesses the orientation wrong, for example when you start filming while the phone lies flat on a table, or turn it after recording has begun. Some older players, editing programs and websites also ignore the orientation setting, so a video that looks fine on the phone shows up sideways elsewhere.
Fast rotation and re-encoding
Because MP4 and MOV files already have this orientation setting, a plain rotation only needs to change it. The video data is copied as it is: an hour long recording is done in seconds, and the quality is identical to the original. This is what Fast (no quality loss) does.
Re-encode turns the picture itself and compresses it again. Use it when a program still shows the rotated file sideways, because that program ignores the orientation setting. It takes longer, roughly in proportion to the length of the video, and the quality is very slightly lower, though hard to notice at normal viewing. Mirroring always needs re-encoding, and so do WebM and MKV files, which cannot store an orientation.
| Situation | What happens | Speed | Quality |
|---|---|---|---|
| MP4 or MOV, rotation only, Fast | Orientation setting changes | Seconds | Identical |
| MP4 or MOV, Re-encode | Picture is turned and saved again | Depends on length | Very close |
| Any mirror | Picture is mirrored and saved again | Depends on length | Very close |
| WebM or MKV | Picture is turned and saved again | Depends on length | Very close |
Which way to turn
Look at the preview and think about where the top of the picture should be. If the top is on the left, choose 90° right; if it is on the right, choose 90° left; if the video is upside down, choose 180°. The turn buttons step 90 degrees at a time, so you can also just click until it looks right.
The size line under the preview helps too: a portrait phone video should end up taller than wide, for example 1080×1920, and a landscape video wider than tall.
- Top of the picture on the left: 90° right
- Top of the picture on the right: 90° left
- Upside down: 180°
- Text reads backwards: Mirror (left to right)
Mirroring a video
Front cameras and many webcams record a mirror image, so writing on a shirt, a whiteboard or a sign reads backwards. Mirror (left to right) fixes that. Flip upside down mirrors the picture top to bottom, which helps with recordings made through a mirror or with a camera mounted upside down.
Choosing both mirrors at once is the same as a 180 degree rotation, so the tool saves it the fast way when the file is MP4 or MOV. The flip video page opens the same tool with Mirror (left to right) already selected.
Rotating on a phone or computer without extra apps
On an iPhone, open the video in Photos, tap Edit, tap the crop icon and use the rotate button in the corner, then tap Done. In Google Photos on Android, tap Edit, then Crop, and use Rotate. On Windows, Clipchamp can rotate videos; on a Mac, QuickTime Player has Edit > Rotate Left and Rotate Right before you save.
The browser tool is handy when you are on a computer without an editor, need a lossless result, want to mirror a video, or work with WebM and MKV files that the built in apps may not open.
Common problems and fixes
- The rotated video still plays sideways in one program: that program ignores the orientation setting. Rotate the original again with Re-encode.
- Rotation is slow: you chose Re-encode, a mirror, or a WebM or MKV file. Long videos take time on slower devices; keep the tab open until it finishes.
- Your browser cannot read the video inside this file: some codecs, such as HEVC from iPhones, cannot be decoded in every browser. Fast rotation still works for MP4 and MOV; for re-encoding try Chrome, Edge or Safari.
- The sound is missing: the result keeps the sound. If the original sound could not be converted, a note under the result says so.
- The video was sideways only on one website: try the Re-encode option, since some upload pages ignore the orientation setting.