How it works
Frame delay rewriting
GIF speed is controlled by per-frame delay values (in 1/100s units). This tool parses every frame's delay and multiplies it by 1 / speed, then rebuilds the GIF binary in your browser — no server, no upload.
Why 0.25× to 4×?
Below 0.25× most GIF viewers hit their minimum frame delay floor (~2cs) and ignore it. Above 4× you lose readable motion. This range covers 99% of real use cases.
Reverse playback
Frames are re-ordered in reverse before the delay is rewritten. Works on any GIF regardless of how many frames it has — great for boomerang-style effects.
100% private, zero upload
Everything runs in your browser using pure JavaScript. Your GIF never touches a server. Works offline once the page loads.