WebM Video Resizer

1. 1

   Add WebM video

   Select your WebM file.

2. 2

   Set target size

   Choose a preset or custom width and height. Use aspect ratio lock to prevent distortion.

3. 3

   Resize

   Run resize. Processing stays on your device.

4. 4

   Download

   Download the result. Choose MP4 for Safari/iOS or WebM for web workflows.

WebM is common for web capture and workflows. Resizing WebM changes frame dimensions for embedding, social specs, or smaller files. You can export WebM or switch to MP4 for devices that prefer H.264.

WebM vs the other formats

Use WebM-focused resizing when your pipeline is VP8/VP9 WebM from screen recorders or downloads. For maximum compatibility (phones, smart TVs, social apps), exporting MP4 after resize is often easiest. MOV suits some Apple-first editors.

Compatibility

WebM plays in most desktop browsers; Safari on iOS historically prefers MP4—choose MP4 output when needed. Match dimensions to your player container to avoid letterboxing surprises.

A target frame rarely has the same shape as the clip you are starting from, and there are only three honest answers to that. This tool asks you which one you want instead of picking silently.

The three choices

• Fit: the whole picture, scaled down until it sits inside the target. Nothing is cropped and nothing is distorted, so the output can end up smaller than the frame you asked for. This is the default and the right answer most of the time.
• Fill: the frame is filled exactly and whatever hangs over the edges is trimmed, centred. This is the answer to "resize for Reels without black bars" — a 16:9 clip becomes a true 1080x1920 vertical with no letterboxing.
• Stretch: the exact frame, aspect ratio ignored. Useful when a specification demands a size and the distortion does not matter; the tool warns you when it would be visible.

If you want the bars but want them to look deliberate — a blurred, coloured or mirrored background rather than black — that is a different job, and the aspect ratio tool does it.

Shrinking a picture means deciding what happens to the detail that no longer fits. The rule that decides it is the resampling filter, and most video tools never let you see it, let alone choose it.

What each one is for

• Lanczos: the default, and the sharpest. It looks at a wide neighbourhood around every output pixel, which is what keeps fine texture readable through a big reduction such as 4K to 720p.
• Bicubic: slightly softer than Lanczos and slightly less prone to ringing on hard edges. A good choice for graphics and screen recordings with a lot of flat colour.
• Bilinear: the simplest smooth option. Fast, soft, and the closest match to what most other resizers do without telling you.
• Nearest: no blending at all. The only correct choice for pixel art and for anything where a hard edge must stay hard.

Scaling is hardware accelerated, so the sharpest filter costs no more time than the simplest one. There is no reason to trade quality for speed here.

WebM can be efficient at moderate bitrates. After resizing, if banding appears, try a slightly higher bitrate or MP4 output. Keep aspect ratio locked for screen captures so UI stays aligned.

Best practices

• Export MP4 when targeting iOS or Safari viewers.
• Use presets to avoid odd dimensions.
• Prefer downscaling for crisp results.
• Preview audio sync after long resizes.

If the size you asked for is the size the clip already is, nothing is re-encoded at all: the compressed frames are copied straight across, which takes a fraction of a second and leaves the picture bit for bit identical.

Powered by optimised video encoding pipelines.

Example use cases

• Resize screen recordings for documentation sites.
• Shrink WebM demos for faster landing-page load.
• Convert wide WebM to vertical for short-form video.
• Produce MP4 copies for mobile review from WebM masters.

Common use cases

• Web performance: Smaller frames for hero or background clips.
• Documentation: Consistent resolution for tutorials and help videos.
• Cross-platform: MP4 handoff for teams on mixed devices.
• Editing pipelines: Intermediate size before color or cuts.
• Storage: Smaller WebM or MP4 copies for archives.

• All video formats (MP4, WebM, MOV)
• Resize MP4
• Resize MOV

• Video resizer
• Video compressor
• Video to GIF
• Video cropper
• Cut video
• GIF maker
• Image to video