Resize Video Online Free — Change Resolution & Aspect Ratio for YouTube, Shorts, TikTok, Instagram (No Upload)
Drop a video here
or click to choose (MP4, MOV, WebM, MKV…)
processed in your browser · never uploaded
Resizes a video to a social-media size or any width × height in your browser. Nothing is uploaded.
A free online video resizer for turning a landscape clip into a vertical 9:16 for Shorts or TikTok, fitting Instagram's square or 4:5, or downscaling 4K to 1080p or 720p — with no editor to install and nothing uploaded. Choose a preset (YouTube 16:9 1920×1080, Shorts/TikTok/Reels 9:16 1080×1920, Instagram 1:1 1080×1080, Instagram 4:5 1080×1350, HD 1280×720 and more) or enter a custom width and height (set one to 0 to keep the aspect ratio automatically). When the aspect ratio changes, pick how to fit: Pad keeps the whole picture with black bars, Crop fills the frame and trims the edges, Stretch distorts to fit. Output is an H.264/AAC MP4 ready to upload to any platform. The key difference from typical online resizers: your video never leaves your device. Everything runs locally via WebCodecs, so there is no upload wait, size cap, account or watermark. The Video Compress tool is for making files smaller; this page is for changing dimensions and aspect ratio. Processing time scales with length and output resolution. A recent Chrome or Edge is recommended.
How to use
- Drop in a video file (MP4, MOV, WebM…).
- Pick a social-media preset or enter a custom width × height; if the aspect ratio changes, choose Pad, Crop or Stretch.
- Press “Resize”, then download the MP4.
FAQ
Is my video uploaded?
No. Loading, resizing and exporting all happen inside your browser on your device — nothing is sent to or stored on a server. That's why there is no upload wait and no size limit. Leaving the page discards any in-progress data.
How do I make a landscape video vertical for Shorts or TikTok?
Choose the preset “Shorts / TikTok / Reels 9:16 — 1080×1920”. Because a wide picture goes into a tall frame, Pad keeps everything with black bars above and below, while Crop cuts a vertical slice from the middle to fill the screen (the sides are trimmed). Crop looks most natural when the subject is centered.
I only want to change the resolution and keep the aspect ratio.
Use Custom and enter just the width or just the height, leaving the other at 0 — it is computed from the original aspect ratio (e.g. width 1280, height 0 turns a 1920×1080 video into 1280×720). The 1920×1080 and 1280×720 presets also resize proportionally when the source is 16:9.
Will upscaling a small video make it sharper?
No. Enlarging only interpolates pixels that aren't there, so it looks softer. Upscaling to meet a platform's recommended size is fine, but it doesn't add detail. Downscaling (4K to 1080p, for example) looks clean.
How is this different from Video Compress?
Video Compress shrinks the file size (target MB or quality). This page changes dimensions and aspect ratio. To fit a platform size and make the file smaller, resize here first and then run Video Compress, or use the resolution cap inside Video Compress.
Which formats are supported, and what is the output?
Input: MP4, MOV, WebM, MKV and other formats your browser can read. Output: H.264/AAC MP4 (WebM in browsers that can't encode H.264); width and height are rounded to even numbers. Audio is carried over, or untick keep audio to drop it. Encoding uses WebCodecs, so a recent Chrome or Edge is recommended.