What is Video Resolution Changer?

Video Resolution Changer lets you downscale or upscale your video to common resolutions like 480p, 720p, 1080p, or 4K. Useful for reducing file size before sharing, meeting platform upload limits, or standardizing footage. All processing is private and runs locally via ffmpeg.wasm.

The resizer uses ffmpeg's scale filter with Lanczos resampling, which keeps edges crisp when downscaling and avoids the blur you get from default bilinear. Aspect ratio stays locked by default, and the custom mode lets you enter exact pixel dimensions for unusual targets like 1280x800 or vertical 1080x1920. Output is H.264 in an MP4 container.

How to use

1. Upload your video file (MP4, WebM, or MOV).
2. Select a target resolution from presets (360p, 480p, 720p, 1080p, 1440p, 4K) or enter a custom width and height.
3. Click Resize and download the resized video.

When to use

• Shrinking a 4K phone recording to 1080p so it fits an email attachment limit.
• Standardising mixed-resolution footage to 720p before importing into a video editor.
• Resizing horizontal video to vertical 1080x1920 for Instagram Stories or TikTok.

Result

Your phone recorded a 4K video that's 2 GB. Select 1080p to shrink it to a manageable size for email while keeping sharp detail.

FAQ

Does upscaling actually improve quality?

No. Lanczos upscaling sharpens the existing pixels but cannot invent detail that was never recorded. A 480p source scaled to 1080p will look softer than a native 1080p capture, just at a larger file size.

Why is my output file larger than the original?

The original was likely encoded with a low bitrate or a more efficient codec like H.265. Re-encoding to H.264 can produce a bigger file, even at the same resolution. Drag the Quality slider toward Smaller file, or pick a lower resolution, to bring the size down.

Will resizing preserve the aspect ratio?

Yes, with Fit (the default): the picture is scaled to fit and any gap is filled with a color or a blurred copy of the video, so nothing is cut off. Switch to Crop to fill the frame edge to edge with no bars (the overflow is trimmed), or Stretch to force the exact dimensions even if it squashes the picture.

What's the largest file I can resize in browser?

Around 500 MB on a typical laptop. ffmpeg.wasm loads the full file into WebAssembly memory, so very large 4K clips or long recordings may run out of address space. Trim first if you hit a memory error.

Can I change the frame rate at the same time?

Not in this tool. Use the video frame rate changer for that. Doing both in one pass would require re-encoding twice, so keeping them separate gives you better control over each step.

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