How to Convert Video Between Formats (MP4, WebM, and More)

A video that will not play is usually a format problem. Your editor rejects the file, a website will not accept the upload, an old device cannot open it, or a clip arrives in something exotic. Converting the video to a common format fixes it. This guide explains the formats and codecs that matter, the difference between the two, and how to choose so your video plays everywhere.

Container vs. codec — the thing to understand

People say "format," but a video file has two layers:

• The container (MP4, WebM, MOV, AVI) — the wrapper that holds the video, audio, and metadata together. This is the file extension.
• The codec (H.264, H.265/HEVC, VP9, AV1) — how the video *inside* is actually compressed.

Two MP4 files can behave differently because they use different codecs. Playback problems often come down to the codec, not just the container.

How to convert a video with this tool

1. Open the Convert Video Format tool.
2. Load your video.
3. Choose the target format.
4. Convert and download.

Everything runs in your browser, so your video is never uploaded.

Choosing a format

• MP4 (H.264) — the universal choice. It plays on virtually every device, browser, and platform. When in doubt, convert to this.
• WebM (VP9/AV1) — efficient and open, great for the web, but less universally supported on older devices.
• MOV — common from Apple devices; convert to MP4 for wider compatibility.
• H.265/HEVC — smaller files at the same quality, but patchier support. Efficient for storage, riskier for sharing.

For maximum compatibility, MP4 with H.264 is the safe answer almost every time.

What conversion costs

Re-encoding a video means decompressing and recompressing it, which can lose a little quality — like re-saving a JPG. To minimize it:

• Convert from the best original, not from an already-compressed copy.
• Use a high-quality setting if the file will be edited further.
• Convert once to your target rather than bouncing between formats.

Related tools

Trim first with Trim Video so you only convert what you need. Shrink the result with Compress Video. Need just the sound? Extract Audio from Video pulls it out.

Common uses

• Make a video play on a device that rejects it.
• Prepare a clip for an editor or platform.
• Convert a phone MOV to universal MP4.
• Move to an efficient codec for storage.

Privacy and limits

Conversion is fully local — no upload, no file-size cap, nothing stored, offline once loaded. Open the Convert Video Format tool to make your video play anywhere.