How to make a GIF from a video, free, with a file size that actually sends
GIFs are huge by nature. The settings that keep a video-to-GIF conversion under 2–5 MB (width, frame rate, colours, length), when to use a short MP4 instead, and a browser tool that converts on your device with a boomerang option.
· 3 min read · 755 views · by the Cortex Digital Hub team
Pick the clip, width, fps and colours; see the size before you export. Runs on your device, boomerang included. Free.
Convert video to GIF → Opens Video to GIF · runs in your browser
A GIF is the least efficient way to store moving pictures ever invented, which is why a six-second clip can come out at 40 MB. It is also still the format some places insist on. Here is how to make one that sends, and when to send a tiny MP4 instead.
Why GIFs are big
A GIF is a stack of images, each limited to 256 colours, with almost no compression between frames. Size is close to width × height × number of frames. A 640 × 360 clip at 20 fps for 10 seconds is 200 frames of 230,000 pixels each: tens of MB. The same clip at 480 × 270 and 12 fps is 120 frames of 130,000 pixels: roughly a quarter of the size.
Nothing about "quality settings" changes that arithmetic; only the four numbers below do.
The four settings that decide the size
| Setting | Sensible choice | Effect |
|---|---|---|
| Length | 2–5 seconds | Linear: half the clip, half the size |
| Width | 480 px (320 for chat, 640 only if it must be sharp) | Quadratic: 480 vs 640 is 44% fewer pixels |
| Frame rate | 12 fps (8 for slow scenes, 15 for fast motion) | Linear: 12 vs 20 fps is 40% smaller |
| Colours | 128 (64 for screen recordings, 256 for photos) | Fewer colours, smaller file, more banding in gradients |
Rule of thumb for a GIF that sends anywhere: 3–5 seconds, 480 px wide, 12 fps, 128 colours. That lands at 1–3 MB for most footage.
Making one in the browser
- Open video to GIF and drop the video (MP4, MOV, WebM, MKV all work; the source stays on your device).
- Set the start and end on the timeline; keep it short.
- Choose width, fps and colours. The size estimate updates as you change them, so you can see the cost of each choice before exporting.
- Optional: Boomerang plays the clip forward then backward, which doubles the frames but makes a 2-second clip loop smoothly without a jump cut. Speed 1.5× or 2× shortens a slow clip without cutting it.
- Export. The encoder builds one global palette for the whole clip, which avoids the flicker you get from tools that re-palette every frame.
If the source is long, trim it first with trim video using the fast, no-re-encode mode; it is instant and lossless.
When to use MP4 instead
For anything longer than about 3 seconds, anything with camera motion, or anything that needs sound, a short MP4 is ten to fifty times smaller than a GIF of the same clip and plays inline in WhatsApp, Slack, Teams, Instagram, X, LinkedIn and modern e-mail clients. Make it with the video compressor at 480p or 720p and a target size of 2–5 MB.
GIF still wins in a few places: CMSs and e-mail templates that only accept image files, Slack custom emoji and reactions, some documentation tools, and anywhere the file must loop without a play button.
Common uses, with settings
- Product demo for a WhatsApp catalogue: 4 s, 480 px, 12 fps, 128 colours, boomerang off.
- Screen recording of a software step for a support reply: 5–8 s, 640 px, 10 fps, 64 colours (UI has few colours; the saving is large).
- Reaction clip for a group chat: 2 s, 320 px, 15 fps, 128 colours.
- Slow pan over a 3D floor plan for a listing: 3 s, 480 px, 12 fps, 256 colours (the render has gradients), boomerang on so it sways rather than jumps.
Why it runs on your device
Encoding a GIF means decoding every frame of the video and re-encoding it; done on a server that means uploading the whole video first and waiting. The Cortex tool uses the browser's own video decoder and encodes the GIF locally, so a 300 MB clip starts converting immediately and nothing is uploaded. The same engine powers the video converter and video resizer.
Frequently asked questions
Why is my GIF 40 MB?
GIF stores every frame as a full image with no real compression, so size is width × height × frames. Ten seconds at 640 px and 20 fps is 200 frames; the same clip at 480 px and 12 fps is 120 smaller frames and a quarter of the size.
What is the best size for a GIF on WhatsApp?
Under 2 MB. WhatsApp converts GIFs to short looping videos anyway, so a 480-px, 10–12 fps, 3–5 second GIF is plenty and sends instantly.
Should I use a GIF or a short MP4?
MP4 for anything over 3 seconds or with real motion: it is ten to fifty times smaller and plays everywhere now, including e-mail clients that show video. GIF for places that still want a GIF file (some CMSs, Slack reactions, old e-mail templates).
Does a GIF have sound?
No. GIF is image-only. If the clip needs its audio, export a short MP4 instead.