HelloResizer

Resize Videos Online, Free

Change video resolution to 1080p, 720p, 4K, or any custom size. Powered by WebAssembly — your files never leave your device.

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How to Resize a Video

  1. Drop your video files — Drag and drop or select MP4, WebM, MOV, or AVI files from your device.
  2. Choose your target resolution — Select a standard resolution (1080p, 720p, 480p, etc.) or enter custom dimensions. Toggle aspect ratio lock as needed.
  3. Download instantly — Click “Resize” and download your resized videos individually or as a ZIP.

Why Resize Videos?

Video files are often much larger than necessary for their intended use. Resizing helps you:

  • Reduce file size for sharing — A 4K video downscaled to 1080p can be 3–4x smaller, making it practical for email, messaging, and social media uploads.
  • Meet platform requirements — Different platforms have different resolution requirements. Resize MP4 files to the exact dimensions each platform expects.
  • Optimise for web embedding — Serving 4K video to mobile viewers wastes bandwidth. Resize to match the actual display dimensions.
  • Save storage space — Batch resize video libraries to reclaim disk space without re-recording.

Supported Resolutions

  • 4K (2160p) — 3840 × 2160px
  • 1440p (QHD) — 2560 × 1440px
  • 1080p (Full HD) — 1920 × 1080px — most common
  • 720p (HD) — 1280 × 720px — good for web
  • 480p (SD) — 854 × 480px
  • 360p — 640 × 360px — smallest practical size
  • Custom — any width and height you need

Also check out our image resizer and PDF resizer — all free and browser-based.

Frequently Asked Questions

Do my videos get uploaded to a server?
No. All video processing happens in your browser using FFmpeg compiled to WebAssembly. Your videos never leave your device.
What video formats are supported?
MP4, WebM, MOV, and AVI. The output format matches your input — an MP4 input produces an MP4 output.
How long does video resizing take?
It depends on the file size and your device's processing power. A 1-minute 1080p video typically takes 30–60 seconds on a modern laptop. Larger files or 4K content will take longer.
Is there a file size limit?
We recommend files under 500MB for smooth processing. The actual limit depends on your device's available memory. If processing fails, try a smaller file.
Will resizing reduce video quality?
Downscaling (e.g., 1080p to 720p) slightly reduces detail but produces a smaller, more practical file. Upscaling won't add detail but will increase file size. Audio is preserved unchanged.
Does it work on mobile?
Video resizing requires significant processing power. It works on modern mobile browsers but will be slower than on desktop. For large files, we recommend using a desktop browser.