Resize a video online
Change the shape of a video for Reels, TikTok, Shorts, Instagram posts or YouTube. Keep the whole picture with bars, or fill the frame and crop. It all happens on your own computer.
- Never uploaded
- No size limit
- No watermark
- Free
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Quick answer: To resize a video, drop it into the tool at the top of this page, pick a shape (9:16 for Reels, TikTok and Shorts, 1:1 for a square, 4:5 for a feed post, 16:9 for YouTube) and press "Resize video". Choose black bars to keep the whole picture, or crop to fill the frame. It happens in your browser, so the video is never uploaded. It is free, with no sign-up and no watermark.
Updated
How it works
- Drop your videoMP4, MOV, WEBM or MKV, any size. It stays on your computer.
- Pick the shape9:16, 1:1, 4:5 or 16:9, or type your own width and height. Then choose bars or crop.
- Resize and downloadYou get an MP4 in that shape, ready to post.
Which shape for which app
| Shape | Size it makes | Used for |
|---|---|---|
| 9:16, vertical | 1080 × 1920 | Reels, TikTok, YouTube Shorts |
| 1:1, square | 1080 × 1080 | Square posts |
| 4:5, portrait | 1080 × 1350 | Feed posts |
| 16:9, wide | 1920 × 1080 | YouTube, TV, presentations |
For any other size, choose Custom and type a width and height from 16 to 4096 pixels.
Bars or crop: what you get
A wide clip does not fit a tall frame, so something has to give. Take a 1920 × 1080 landscape video made 9:16:
- With bars the whole picture stays. It is shrunk to fit the width, so it fills only the middle third of the height, with black above and below.
- With crop the picture fills the whole frame. It is cut from the middle, so you keep about a third of the width and lose the left and right edges.
Choose bars when everything in the shot matters, such as a screen recording or a group of people. Choose crop for a clip with one subject in the middle. A video that already has the shape you pick is left with no bars and nothing cut off.
Do you need an AI tool to resize a video?
No. Resizing is a fixed calculation: the picture is scaled to the new shape, then filled with bars or cropped. No AI is involved. What it does not do is follow a face or a moving subject to keep it in a 9:16 crop: the crop always comes from the middle. Many online resizers upload your video to a server first; this one runs on your computer and the file stays there.
Measured, not promised
Timed on 21 Oct 2026 in Chrome on a 2019 Intel MacBook (an older laptop) with a one-minute 720p clip with spoken sound. Newer computers are faster; real files vary. More results.
Why your video never leaves your computer
Your video is processed by your own computer, inside this tab, and never uploaded. That is why there is no size limit and no watermark. How it works.
Questions
Is the whole picture kept?
With bars, yes. With crop, the edges are cut off. The tool shows the old and the new size before you start.
Does it make the file smaller?
Not as a goal. A tall 1080 × 1920 video can be bigger than the clip it came from. To shrink the file, use the video compressor afterwards.
Which videos work?
MP4, MOV, WEBM and MKV, including phone videos in portrait or landscape.
Is my video uploaded?
No. It is processed inside this browser tab and saved straight back to your computer.