GIF Compressor

GIFs get big fast: every frame is a full picture with up to 256 colours. This compressor rebuilds a GIF with ffmpeg so it takes less space — one carefully chosen palette for the whole animation, only the changed part of each frame stored, and optionally fewer colours, smaller dimensions or fewer frames. Timing, looping and transparency are kept. It runs in your browser (the engine is a one-time 30 MB download); your GIFs are not uploaded.

How to use this tool

1. Choose one or more GIF files.
2. Pick how many colours to keep — 128 is usually indistinguishable, 64 is a big saving.
3. Optionally scale the GIF down or drop frames for a much smaller file.
4. Press Calculate, compare the sizes and download.

Formula

GIF size ≈ frames × changed pixels per frame × bits per pixel ÷ LZW ratio

Halving width and height leaves a quarter of the pixels. Going from 256 to 64 colours lowers bits per pixel from 8 to 6 and makes LZW compression find more repeats. Dropping every second frame removes half the frames while each remaining frame is shown twice as long. If the new file is not smaller, you get the original back.

Example

A 6.2 MB reaction GIF (480 × 270, 90 frames, 256 colours) at 64 colours and 75% size typically comes out around 2.0–2.8 MB; adding "drop every second frame" brings it near 1.2 MB, under many chat apps' limits.