How the GIF is made
The tool reads frames from your chosen range at the frame rate you set, scales them to the width you choose, reduces each to a palette of up to 256 colours, and writes them into an animated GIF with the right delay between frames. It runs in a background worker, so the page stays responsive, and the progress shows the size so far.
Settings that control size
- Length: the biggest factor. Every frame is stored separately, so 6 seconds is twice the size of 3.
- Frames per second: 10 fps looks smooth enough for most reactions and demos; 15 to 20 fps for fast motion. Each step up adds frames.
- Width: size grows with the area, so 480 px wide is about 1.8 times 360 px.
- Colours: 128 colours is a good default; 64 or 32 for flat graphics and screen recordings; 256 for photographic scenes.
- One palette or per frame: a single palette for the whole GIF is smaller and avoids flicker between frames; per-frame palettes suit clips whose colours change a lot (a scene cut from indoors to a sunset).
- Dithering: smooths gradients, adds a little size.
Timing
GIF frame delays are stored in hundredths of a second, so 15 fps (6.67 hundredths per frame) cannot be represented exactly. The tool alternates 6 and 7 hundredths so the GIF runs at the right overall speed. Browsers slow down GIFs with delays under 2 hundredths, so frame rates above 20 fps are not offered.
Where GIFs are accepted
Messaging apps and forums often limit GIF size: check the destination's limit and use the estimate to stay under it. On many social platforms an uploaded GIF is converted to video anyway, so a short MP4 may look better. For websites, a muted, looping MP4 or WebM is far smaller than a GIF and plays everywhere.
Why it is slower than a desktop app, and when to use HandBrake
This tool uses your browser's own video encoders through WebCodecs, often the same hardware encoders a desktop app would use, but it runs inside a browser tab with a fraction of the computer's memory and without the tuned encoders desktop apps ship. Short clips are quick; a 10-minute 1080p video can take several minutes on a laptop and longer on a phone. The tool refuses files that are likely to run out of memory rather than failing halfway. For long videos, 4K footage, batches of large files, or precise control over the encoder, use HandBrake, which is free, open-source and much faster for heavy work.
Browser support and troubleshooting
The line at the top of the tool lists the video and audio codecs this browser can encode. Current Chrome and Edge on Windows and Mac handle H.264, VP9 and AV1 with AAC and Opus; Safari adds HEVC; Firefox supports WebCodecs from version 130. If a file will not open:
- "This browser cannot decode…" usually means HEVC (H.265) video, common from iPhones, in a browser without HEVC support. Try Safari or Edge on a computer with hardware HEVC, or convert it on the phone (Settings › Camera › Formats › Most Compatible for future videos).
- "Cannot read this file's format" means an old or unusual container such as AVI, WMV or FLV that browsers cannot read. Convert it with HandBrake first.
- It stops or the tab reloads on long or 4K videos: the tab ran out of memory. Trim the video into parts, close other tabs, or use a desktop app.
- Very slow on a phone or an older laptop: the browser may be using software encoding. Shorter clips and lower resolutions help.
GIF or video loop?
| GIF | Muted MP4 or WebM loop | |
|---|---|---|
| Size for 5 seconds at 480 px | Often 2 to 6 MB | Often 200 to 600 KB |
| Colours | 256 at most | Millions |
| Plays in email | Yes, in most email apps | Rarely |
| Plays in chat apps and forums | Yes | Usually, as a video |
| Websites | Works, but heavy | Best choice |
Use a GIF where video does not play, such as email newsletters, some forums and documentation tools. Elsewhere, a short video is smaller and sharper.
GIFs from screen recordings
Screen recordings make excellent GIFs: flat colours need few palette entries and little changes between frames. Use 64 colours, one palette, dithering off and 8 to 10 fps for software demos; they stay small even at 640 px wide.
Privacy
Your video never leaves your device. It is read and written in the browser tab; there is no upload, no server-side processing and no account. You can disconnect from the internet after the page has loaded and it still works. Free use has no watermark and covers files up to 500 MB and 10 minutes; the A$9 lifetime licence removes those limits (your device's memory still applies), queues up to 20 files and saves presets.