Free GIF Speed Changer

The GIF format controls animation timing through a per-frame delay value stored in the Graphic Control Extension block of each frame. The delay is measured in centiseconds (hundredths of a second). A value of 10 means 100 ms per frame — an effective rate of 10 FPS. A value of 4 means 40 ms per frame, equivalent to 25 FPS.

Changing GIF speed means multiplying or dividing every frame's delay by the selected multiplier. Slowing a GIF to 0.5x doubles all delays — each frame lingers twice as long, halving the apparent playback speed. Speeding up to 2x halves all delays. Crucially, no frames are added or removed; only the timing metadata changes. This is different from video playback speed adjustment, which can interpolate new intermediate frames for smoothness.

Most browsers enforce a minimum frame delay of 20 ms (2 centiseconds). Any delay value lower than 2 centiseconds is silently clamped to 2 centiseconds (20 ms), meaning the practical maximum frame rate in a browser is ~50 FPS regardless of what is written in the file. If you speed up a GIF whose frames already have short delays, the browser's floor will cap the visible speed improvement.

PTS manipulation: In video terminology, PTS (Presentation TimeStamp) is the value that tells a decoder when to display each frame. The GIF equivalent is the cumulative sum of frame delays. When this tool adjusts GIF speed, it rewrites the delay for every Graphic Control Extension block in the file — effectively rescaling the entire PTS timeline. Because only delay metadata is modified, the pixel data for each frame is untouched. File size remains essentially identical to the original — the delay fields account for just a few bytes per frame out of the total file.