Video Converter
Convert between MP4, WebM, and GIF, and optionally trim a clip — processed entirely in your browser using a WebAssembly build of FFmpeg. The first use on any visit downloads a one-time ~31MB engine (cached after that); videos up to 200 MB are never uploaded to a server.
This page doesn't show ads — it requires browser security settings (cross-origin isolation) that aren't compatible with third-party ad content.
Click to upload or drag and drop
MP4, WebM, MOV, AVI, MKV, or other common video formats
Why this page loads a large file first
Video processing is genuinely heavy work — this tool loads a real build of FFmpeg compiled to WebAssembly (~31MB, downloaded once and cached by your browser), the same engine behind most video conversion software. That's a meaningfully larger download than this site's other tools, and processing itself can take anywhere from a few seconds to several minutes depending on your device and the video's length and resolution.
Practical limits
Everything runs in your browser tab's own memory, which has real limits — WebAssembly itself caps addressable memory at 2GB, and performance degrades well before that point. This tool enforces a 200 MB file size limit to keep results from hanging your tab, and even files well under that limit can take a while for longer or higher-resolution clips.
About the GIF option
Converting to GIF automatically reduces the frame rate to 10fps and scales the width to 480px, since GIF has no real video compression — an unscaled, full-framerate GIF from typical footage would be enormous. GIFs also never include audio, since the format doesn't support it.
Trim times
Trim start and end accept seconds (90), minutes and seconds (1:30, also 90 seconds) or hours, minutes and seconds (1:00:00, which is 3,600 seconds). Decimals work: 1.5 is a second and a half. Leave one blank to trim only the other end, or both blank to keep the whole video. The parts of a time are simply added up without a range check, so 1:90 is read as 150 seconds.
Anything else, such as a time with four parts or letters, shows "Trim times should look like 90 (seconds), 1:30, or 1:00:00." An end that is not after the start shows "The end time must be after the start time."
What a GIF looks like
A GIF is made at 10 frames per second with a width of 480 pixels and a height that keeps the proportions. A 1920 × 1080 video becomes 480 × 270, and a smaller 640 × 360 clip is enlarged to the same 480 × 270. A 12-second clip gives about 120 frames. There is no audio in a GIF.
Names, settings and file checks
- Nothing starts when you drop a file. Choose the format and trim times, then press Convert. After a result, Change the settings returns to these options without choosing the file again.
- The output is named after your file with the new ending: clip.mov to MP4 gives clip.mp4. MP4 uses H.264 and WebM uses VP9.
- The file must be reported by your browser as video, and up to 200 MB. Above 20 MB a warning says conversion on your own device can take a very long time; the page notes one test where a 5 MB 720p clip took about 2 minutes.
Frequently asked questions
Why does this tool download something before it can convert my video?
It loads a real, WebAssembly-compiled build of FFmpeg — the same engine most video software is built on — since browsers have no built-in way to transcode video formats. That download is roughly 31MB, happens once per visit, and is cached by your browser afterward.
Why doesn't this page show ads?
Video processing this heavy requires a browser security mode (cross-origin isolation) that most third-party ad content isn't compatible with, so this specific page runs without ads rather than risk breaking the conversion.
How large a video can I convert?
Up to 200MB. Processing happens entirely in your browser tab's own memory, which has real limits — very large or long videos can be slow or, on lower-memory devices, fail to complete.
Can I trim without converting the format?
Choose the same format as your source file and set a trim start and/or end time — the file will be re-encoded to that format with just the trimmed range kept.
How do I enter a trim time of one minute thirty?
Type 1:30, or 90. Both mean 90 seconds. For one hour, use 1:00:00 or 3600.
Why is the GIF so small compared with my video?
It is scaled to 480 pixels wide and limited to 10 frames per second, because a GIF has no real video compression. A video at 1920 × 1080 becomes 480 × 270.
Why was my video file refused?
The tool checks the type your browser reports, which must say video. A file whose type the browser does not recognize is refused with "Please choose a video file", even if another program can play it.