Why is my GIF so large?

What makes a GIF big

• MDN explains that each pixel in a GIF is a single 8-bit value pointing into a palette, and that palettes have up to 256 entries.
• The GIF specification says each image in the file is made of an Image Descriptor, an optional Local Color Table, and the image data. A Local Color Table belongs to the single graphic that follows it.
• In our tool, every frame is saved as a full picture with its own palette of up to 256 colors. We checked this in our code on 2026-10-13. Nothing is shared between frames.
• So the file grows with the number of pixels in each frame, and with the number of frames.

What we tested

We ran our Video to GIF tool on a 6-second, 1080p test video that we generated ourselves, starting at 0 seconds. We counted the frames and measured the size of each result with ffprobe on 2026-10-13.

• Small, 3 seconds: 320 by 568 pixels, 30 frames, 430 KB.
• Medium, 3 seconds: 480 by 854 pixels, 36 frames, 917 KB.
• Large, 3 seconds: 640 by 1138 pixels, 45 frames, 1.8 MB.
• Medium, 5 seconds: 480 by 854 pixels, 60 frames, 1.5 MB.

In these four runs the file size stayed between 0.055 and 0.079 bytes for every pixel in every frame. Going from 3 to 5 seconds at Medium added 67% more frames and made the file 69% bigger.

The picture decides too

The test video is a computer-generated pattern, and it makes small GIFs. On a real iPhone recording (our own validation run on iOS 18.7 on 2026-09-20), the Small setting for 3 seconds gave a 2.15 MB GIF. That is about five times the size of the 430 KB we measured at the same size and frame count. We did not test which kinds of scenes give smaller files.

Our page shows an estimate before you start. On the test video, the estimates were 5.8 to 8.3 times higher than the real files. On the iPhone recording, the estimate for that setting was 2.5 MB against 2.15 MB. Treat the estimate as a cautious upper figure.

What you can do

1. Make the GIF shorter. Fewer frames means a smaller file.
2. Choose a smaller size. Small is 320 pixels wide, Medium 480 and Large 640. In our runs the frame rate also went up with the size, from 10 to 12 to 15 frames a second.
3. Make it with Video to GIF. It runs in your browser, and your video is not uploaded.
4. For a long clip, consider another format. MDN suggests considering WebP, AVIF or APNG for animation sequences. Our tool makes GIFs only.

More plain answers are in all guides.