Frame rate, measured in frames per second (fps), is how many still images play each second to create motion. Higher fps looks smoother but adds more frames — and every frame makes a GIF bigger.
For GIFs, 10–15 fps is the usual sweet spot: smooth enough to look good, low enough to keep the file reasonable. Dropping from 30 fps to 12 fps can cut a GIF's size by more than half with little visible difference.
When you convert a video to GIF you can set the fps to balance smoothness and size.
What frame rate does to a GIF
Frame rate is how many images play per second, and in a GIF it maps almost directly onto file size: doubling the rate roughly doubles the number of frames, and each frame is stored nearly independently. Video can absorb a higher frame rate cheaply because it stores differences between frames. GIF cannot, which makes frame rate one of the three big levers on how large your file ends up.
What rate to actually use
For most GIFs, 10 to 15 frames per second looks fine and is the standard range. Screen recordings and interface demos read perfectly at 10. Human motion generally wants 12 to 15. Going to 24 or 30 doubles the file for smoothness few people notice in a small looping clip. Below about 8, motion starts to read as a slideshow rather than movement — occasionally a deliberate effect, usually not.
Frame rate and delay are the same setting
GIF has no frame rate field. Each frame carries a delay, expressed in hundredths of a second, and the apparent frame rate is simply the consequence: a 10 ms delay per frame is 10 fps. This detail explains a common annoyance — many browsers silently clamp very short delays to a minimum, so a GIF authored at 50 fps may play more slowly than intended and differently across browsers.
Changing speed afterwards
Because there are no in-between frames to interpolate, speeding a GIF up means shortening delays or dropping frames, and slowing it down means lengthening delays. Speeding up is usually clean and often shrinks the file. Slowing down past roughly half speed starts to look stuttery, since the same number of frames is stretched over more time. If a clip genuinely needs to be slower and smooth, re-export from the original video at a higher frame rate instead.