Converting MP4 to GIF, step by step
- Load the MP4. Drop it on the dark panel or tap Choose a video. Nothing uploads; the file is read by this tab only.
- Trim. Set start and end. Two to four seconds is the sweet spot for a reaction GIF; every extra second adds frames.
- Size it. Under Crop & size, 480 px wide suits chats, 320 px suits Discord and forums, 128 px suits emoji.
- Pick fps and colours. 12 fps looks smooth for most clips. Keep 256 colours unless you need a smaller file.
- Check the meter, then Make GIF. The estimate comes from a real trial encode, and the finished file shows its exact size.
Why the GIF is bigger than the MP4
An MP4 uses a modern video codec (usually H.264) that stores one full picture every so often and then only the motion between pictures. GIF, a 1989 format, can only compress each frame with LZW, a lossless scheme that works well on flat colour and badly on camera noise. So a 2 MB, 10-second phone clip can become a 20 MB GIF at the same size. That is normal, not a bug. The fixes, in order of impact: smaller width, lower frame rate, shorter clip, fewer colours.
If the place you are posting accepts MP4 or WebP, those stay smaller and sharper. X, for example, converts uploaded GIFs to video anyway. Use GIF when you need it to play everywhere: email, Slack emoji, old forums, README files.
Which MP4 files work
MP4 is a container; what matters is the codec inside. H.264 decodes in every modern browser. HEVC (H.265) and AV1 MP4s decode where the device has support (Safari on Apple devices handles HEVC; most recent Chrome and Edge builds do too on supported hardware). Anything the browser can't decode falls back to ffmpeg.wasm.
The converter first asks your browser to decode the file with its built-in video decoder, the same one that plays videos on web pages. If the browser can't (an unusual container or codec), it loads ffmpeg.wasm, a WebAssembly build of FFmpeg, and converts the first 60 seconds to an editable copy right on your device. That download is about 32 MB, happens once, and still sends nothing of yours anywhere.
Questions
Is this MP4 to GIF converter really free?
Yes. There is no account, watermark or export limit, because the work happens on your device rather than on a paid server.
Does my MP4 get uploaded?
No. The video is decoded by your browser and encoded to GIF in this tab. Only the optional caption helper sends the words you type to an AI model, never the video.
How long can the GIF be?
The trim is capped at 30 seconds, but long GIFs get large quickly and can exhaust phone memory. For sharing, stay under about 6 seconds, which is also what GIPHY recommends.
Why does my GIF look grainy?
GIF can only use 256 colours per frame, so smooth gradients are approximated with a dot pattern called dithering. Try Diffusion dithering for smoother gradients, or export animated WebP, which has no 256-colour limit.