GIF files get large quickly. A few seconds of animation can be 10 MB or more, which is too big for many chats, emails and web pages, and slow to load on a phone. There are only three ways to shrink one: fewer pixels, fewer frames and fewer colors.
This compressor gives you all three. Choose a smaller width, keep every second or third frame, and cut the palette from 256 colors down to as few as 32. It shows the size before and after, and plays the result so you can judge the quality. Everything runs in your browser and the GIF is never uploaded.
Which setting saves the most
Size comes first. At 50% of the width a GIF has a quarter of the pixels, and the file shrinks by roughly that much. Most GIFs are viewed small, so this often costs nothing you can see.
Frames come second: keeping every second frame nearly halves the file and keeps the speed, with slightly less smooth motion. Colors come last. 128 colors is hard to tell from 256 on most clips; 64 and 32 show banding in skies, skin and gradients but work for screen recordings and flat graphics.
When a GIF will not get small enough
If a GIF is still too large at half size, with every second frame and 64 colors, the clip is too long or too detailed for the format. A video is the better choice: the same clip as an MP4 is usually far smaller and looks better.
Use the GIF to MP4 converter for that. To make a new, small GIF straight from a video, use the video to GIF converter, which lets you set the size and frame rate from the start.