Video Resizer
Browser + ServerChange video aspect ratio for any platform. Five background modes — solid, blurred copy, gradient, image, or AI-generated — fill the letterbox cleanly. Browser-based, no upload.
Tap to select videoSelect a video to resize
MP4, WebM, MOV
or drag and drop
How It Works
Select a video
Drop in any MP4, WebM, or MOV. The video stays on your device.
Pick output + background
Choose a TikTok / Reels / YouTube / Instagram preset, then pick a background mode for the padded area.
Download
Export as WebM (VP9 + Opus) with synchronized audio. No watermark.
Frequently Asked Questions
Is the video resizer free?
Yes — free with no signup and no watermark. Resizing happens in your browser; AI background generation uses our free FLUX endpoint with reasonable rate limits.
Do my videos get uploaded?
No. The video stays in your browser. Only the AI background option sends a short text prompt (no video data) to our image generator.
Which output sizes are available?
Presets for TikTok / Reels (9:16 1080×1920), Instagram square (1:1) and feed (4:5), YouTube 1080p / 720p (16:9), ultra-wide (21:9), original, and any custom dimensions.
What background options exist?
Solid color, blurred copy of the video itself (mobile-style), custom linear gradient, your own image, or an AI-generated background from a text prompt.
What's the difference between fit, fill, and stretch?
Fit keeps the entire video visible (with letterbox/pillarbox padding). Fill crops to completely fill the output. Stretch warps the video to the new aspect ratio without padding.
Does it work on mobile browsers?
Yes. Works in Safari and Chrome on iOS 16+ and Android. AI background generation works on all devices.