GIF Speed Decrease: Change the Speed of a GIF

How it works

1. 1Upload one GIF or animated WebP file. The browser shows a preview and the frame count.
2. 2Keep the Speed multiplier at 0.5x for half speed, or pick a preset or enter a value from 0.25x to 4x.
3. 3Or choose Same delay for every frame and enter a value from 20 to 60000 ms.
4. 4Check the forecast line to see the new playing time.
5. 5Choose Save as: Same as the original, GIF or Animated WebP, then click Change speed.

Example output

Original GIF, 80 ms per frame, 1.9 s, 88 KB

Slowed to 0.5x, 160 ms per frame, 3.8 s, 90 KB

What this GIF speed decrease tool does

The tool changes only the delay of each frame. It decodes the animation once, copies the pixels and writes the result once. The pictures, the number of frames, the size and the loop count stay the same. Above 1x is faster and below 1x is slower, so the same tool covers both directions.

Our server does the work with sharp, an image library built on libvips. This is ordinary image processing, not artificial intelligence. The file is sent to our server, so it is not edited in your browser.

• Speed decrease uses a multiplier below 1x.
• Speed increase uses a multiplier above 1x.

GIF speed decrease: slow a GIF down

A GIF speed decrease makes every frame stay on screen for longer. The default of 0.5x doubles each frame's delay, so the playing time roughly doubles. Values below 1x slow the animation further, down to 0.25x.

In our test, we used a generated animation of 24 frames at 80 ms each, which is 1.9 s in total. At 0.5x the playing time went to 3.8 s, and at 0.25x it went to 7.7 s. Your results will depend on your file.

GIF speed up: make a GIF faster

Use a multiplier above 1x to make a GIF faster. A 2x multiplier halves every delay, and 4x is the top of the range. In our test, the same 24-frame animation went from 1.9 s to 1.0 s at 2x, and to 0.5 s at 4x.

The tool does not add or drop frames. A GIF that already has short delays may not reach the speed you ask for. The result panel tells you when that happens.

Speed multiplier or the same delay for every frame

The Speed multiplier scales the existing delays, so the original timing between frames is kept. Presets are 0.25x, 0.5x, 0.75x, 1.5x, 2x, 3x and 4x. The multiplier can be set with the slider or the number box.

Same delay sets every frame to one value from 20 to 60000 ms. This replaces the original timing, so use it when you want all frames to have the same delay. In our test, a same delay of 40 ms gave 1.0 s, the same as 2x. A same delay of 20 ms gave 0.5 s, the same as 4x.

Why a GIF cannot be faster than 20 ms per frame

Major web browsers play any frame delay of 10 ms or less as 100 ms. Because of this, the shortest delay that really makes a GIF faster is 20 ms, which is 50 frames per second. A speed that needs a delay under 20 ms is held at 20 ms.

The result panel says how many frames were held and shows the effective speed. In our test, a 24-frame GIF at 20 ms per frame was asked for 2x. All 24 frames were held at 20 ms, so the effective speed stayed at 1x. GIF timing uses steps of 10 ms, so delays round to the nearest 10 ms in GIF output. WebP keeps single milliseconds.

Animated GIF speed: frames, loop and playing time

Animated GIF speed depends on timing, and the frames themselves stay as they are. The result panel shows the frame count, playing time and loop, such as "N frames, X s, loops forever" or "plays N times". Loop 0 means the animation loops forever.

The Animation row in the result panel shows the new values after the job ends. If you need to cut frames or shorten the clip, use the GIF trimmer page for that job instead.

File size after changing the speed

Only the delays change, so the file size stays about the same. The GIF is written again, so small differences can still occur. In our test, a 320 x 240 px, 24-frame GIF went from 88 KB to 90 KB at 0.5x.

Results vary with the file. A result larger than 20 MB fails with an "output too large" message instead of returning a cut-off file.

Save as GIF or animated WebP

You can save as Same as the original, GIF or Animated WebP. GIF output uses at most 256 colours, with dithering, and each pixel is either fully transparent or fully opaque. Animated WebP output is lossy, and the quality slider starts at 80.

In our test, a 0.5x result saved as animated WebP was 60 KB. Choose the format that suits your use, and check the file size in the result panel.

Limits for animations

The limits are checked from the file header before the animation is decoded. Signed in, you can use up to 300 frames and 64 MP in total pixels, where total pixels equal width x height x frames. Without an account, the limit is up to 100 frames and 16 MP.

The price is the base 1 credit per file. You also pay 1 credit for each started 10 megapixels of decoded frames beyond the first 10 megapixels. Without an account, the tool is free within the daily limit. A job over a limit fails, and its credits are returned.

Which files the tool accepts

The tool accepts GIF and animated WebP files. A PNG, JPG or other file is refused with a message that says so. The file type is read from the file content, not from the name, so a text file renamed to .gif is refused as an unsupported image.

The free web tool accepts up to 5 MB per file, with up to 30 files per day per visitor. Each frame can be up to 16 MP (4096 x 4096). Signed-in users can upload up to 10 MB per file. The web tool handles one file at a time.

Change GIF speed from code

Send a POST request to https://api.aiipworld.com/v1/image-jobs with the raw file bytes as the body, not JSON or multipart. Set Content-Type to image/gif or image/webp. Authorize with Authorization: Bearer and your API key, or with x-api-key.

Add op=gif_edit and action=speed to the query string. Every action accepts only its own parameters, and unknown names are rejected. For animations, send timeout_sec=60, which is the maximum. The API takes one request per file, and there is no batch endpoint and no webhooks yet.

The response is 202 with a job_id. Poll GET /v1/jobs/:id until the job succeeds, fails or times out. The download_url is a short-lived signed link. Errors include 400 for an unsupported image or invalid parameters, 413 for a file that is too large, 402 for insufficient credits and 429 for rate limiting. Below the tool, the page shows a ready cURL, Node and Python example that follows the settings you choose. The full docs are at /docs/#image-jobs.

Privacy: what happens to your file

Your file is sent to our server and used only to make the result. It is deleted as soon as the job ends, whether it succeeds or fails. You must have the right to use anything you upload, as set out in the Acceptable Use Policy.

In the free web tool, the result is deleted after 10 minutes. No history is kept, and download links are short-lived. Failed and timed-out jobs are refunded.

Questions