Leave the height at zero to keep the original proportions. The animation timing and looping are preserved, and the file never leaves your computer.
Private by design
Most online GIF makers and video cutters upload your file to their servers, process it there and keep it for hours. GifKiln works differently: FFmpeg, the same engine used by professional tools, runs inside this browser tab. Your files are never uploaded, there is no queue, and there is no watermark.
Frequently asked questions
Will resizing lose the animation?
No. Every frame is resized and the frame timing is kept, so the GIF plays exactly as before, just at the new size.
Are my files uploaded?
No. GifKiln runs FFmpeg inside your browser with WebAssembly. Your files are read and processed on your own device and are never sent to a server.
Is GifKiln free?
Yes. Every tool is free with no watermark and no account. Very large files are limited to keep the browser stable.
Why does the first run take a moment?
The first time you use a tool the browser downloads the FFmpeg engine (about 32 MB). It is cached, so later runs start instantly and even work offline.
Which browsers are supported?
Current Chrome, Edge, Firefox and Safari on desktop and mobile. Chrome, Edge and Firefox use a faster multi-threaded engine; other browsers use a single-threaded one that is slower but produces the same result.