Where GIF size comes from
A GIF’s size is roughly width × height × number of frames. Every way of shrinking one reduces one of those three:
- Smaller dimensions — going from 800px to 560px wide roughly halves the file. A GIF larger than the space it’s shown in is just wasted bytes.
- Fewer frames — dropping a 25fps GIF to 12–15fps is hard to notice for most content.
- Shorter loop — trimming dead frames at the start and end costs nothing in quality.
This page starts with a 5MB target. Drag the slider (or type a number) to whatever your platform allows. “Sharper” keeps the dimensions and lowers the frame rate first; “Smoother” keeps the motion and shrinks the dimensions instead.
Transparent GIFs
GIFs with transparent areas are supported. Transparent pixels are filled with the “Outside background” color, so set it to the background of the page where the GIF will appear for the cleanest edges.
If it still won’t fit
When even the smallest combination is over the target, GIFsize tells you instead of silently producing a bad file. Speeding the clip up 1.5–2× is usually the most effective next step — the same motion in fewer frames — followed by trimming the range.