Recut

Free video resizer for TikTok, Reels and Shorts

Choose a video, pick the shape (9:16 for TikTok, Reels and Shorts, 1:1, 4:5 or 16:9), choose whether to keep the whole picture or crop to fill, trim the start and end if you like, and download an MP4. It all runs in your browser, so the video never leaves your device.

Want captions, music and cuts done for you?

Try Recut. Attach your video, say what you want in plain words, and Recut plans the steps, shows any price first and makes it.

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How to use it

  1. Choose a video, or drop it on the box. MP4 and MOV from a phone, WebM and most other common formats work, up to 500 MB.
  2. Pick the shape. 9:16 is the full-screen vertical shape TikTok, Instagram Reels and YouTube Shorts use; 1:1 is square; 4:5 is the taller feed shape; 16:9 is widescreen for YouTube and most screens.
  3. Choose the fit. "Keep the whole picture" fits all of your video inside the new frame and fills the empty space with a blurred, darkened copy of the video or with black bars. "Fill the frame" crops the picture to the new shape, keeping the centre. The preview shows one frame with your choice.
  4. Trim if you need to: type a start and an end in seconds (12.5) or minutes and seconds (1:05). Leave them empty to keep the whole video.
  5. Press Convert to MP4, wait for the bar to fill, check the result in the player and press Download MP4.

How it works

The converter is FFmpeg, the open-source video tool, compiled to WebAssembly by the ffmpeg.wasm project. Your browser downloads it (about 9 MB, version 0.12.10 from the jsDelivr CDN) only when you press Convert the first time, then keeps it in its cache. It runs in a background worker that reads your file straight from your disk, so there is no upload, no account and no watermark.

Fill scales the video until it covers the whole frame and crops what spills over at the sides (or the top and bottom), keeping the middle. Fit scales the whole video to fit inside the frame. Blurred bars come from a tiny copy of the video, blurred, darkened by 30% and stretched to fill the frame behind it; black bars are plain black padding.

The download is an MP4 with H.264 video and AAC stereo sound at 128 kbps, the most widely accepted combination for upload. It is set to 30 frames a second, encoded at constant quality (CRF 23), and has its index at the front so it starts playing straight away. A trim is re-encoded rather than cut at the nearest keyframe, so it starts close to the time you typed.

Output sizes

Shape1080p720pTypical use
9:161080×1920720×1280TikTok, Reels, Shorts, Stories
1:11080×1080720×720Square posts
4:51080×1350720×900Instagram and Facebook feed
16:91920×10801280×720YouTube, widescreen

These are the common full-HD and HD sizes for each shape. Each app has its own upload rules (length, file size, safe areas for text), and they change, so check the app's own help pages before an important post.

Limits

Files over 500 MB are refused, because the whole conversion has to fit in the memory your browser gives one tab. Phones have less of it than computers; if a conversion runs out of memory, try 720p, a shorter trim, or a computer.

It is slower than a desktop app: the browser version of FFmpeg uses one processor core. A short clip takes from several seconds to a few minutes, depending on its length, the size you choose and your device. 720p is quicker than 1080p.

The crop is always centred. It does not follow a face or a moving subject.

HDR video (for example from a recent iPhone) is converted without tone mapping, so colours can look flatter than the original.

It changes the frame and the length only. It does not add captions, music, cuts or effects.

Questions

Is this video resizer free?

Yes. There is no sign-up, no watermark and no limit on how many videos you convert. It costs us nothing per video because the work happens on your device.

Is my video uploaded anywhere?

No. The page downloads the FFmpeg converter to your browser, and the converter reads your file directly from your device. The video and the result never leave it.

How do I make a video 9:16 for TikTok, Reels or Shorts?

Choose the video, pick 9:16, choose blurred bars, black bars or fill, and press Convert to MP4. At 1080p the result is 1080×1920, the usual full-HD vertical size.

What is the difference between fit and fill?

Fit keeps the whole picture and adds bars, blurred or black, where it doesn't reach the edges. Fill covers the whole frame and crops off what doesn't fit, keeping the centre. Fill suits a person talking near the middle of the shot; fit suits screen recordings and wide shots.

Does it work on a phone?

Yes, in a recent Chrome, Safari, Firefox or Edge, but phones have less memory and are slower. Short clips at 720p work best on a phone; long or large videos are better on a computer.

Why did my conversion fail?

Usually the browser ran out of memory, or the file uses a codec the browser version of FFmpeg can't read. Try 720p, a shorter trim, closing other tabs, or exporting the video as H.264 MP4 from your phone or editor first.

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