キレ

Change GIF speed

In your browser, no upload

GIF

0.5× · 0.75× · 1.5× · 2× · 3× · not re-encoded

GIF

Faster or slower, not re-encoded

Specification

7 rows
Change GIF speed specification
ItemValueNotes
InputGIF, animatedA single-frame GIF has no speed to change
OutputGIFThe same frames with new delays
Speed0.5× · 0.75× · 1.5× · 2× · 3×2× to begin with
PicturesCopied as storedOnly each frame’s delay is rewritten
Delay unit1/100 sRounded; the total stays within 1/100 s
Shortest delay20 msBrowsers play 0 and 10 ms as 100 ms
Processed inThis browserNot sent to a server

What happens

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What happens, and why

Drop an animated GIF and pick how much faster or slower it should play. Every frame of a GIF stores its own delay — how long it stays on screen — and that number is the only thing this page changes. The pictures, their colours and their positions are copied byte for byte, which is why the badge says the file was not re-encoded. It happens inside this browser; the GIF is not sent to a server.

A delay is stored in hundredths of a second, so not every speed divides evenly: twice as fast as 70 ms is 35 ms, which a GIF cannot hold. Each delay is rounded to the nearest hundredth and the difference is carried into the next frame, so the whole animation stays within 1/100 s of the exact length. The line under the result says when that happened.

Two habits of browsers decide how fast a GIF can go. Chrome, Firefox and Safari play a delay of 0 or 10 ms as 100 ms, so a frame stored that way is timed from the 100 ms it was actually seen for. For the same reason the shortest delay that plays as written is 20 ms, fifty frames a second. A frame that would need less is held at 20 ms, and the line under the result gives the speed the GIF really has.

FAQ

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Does changing the speed lower the quality

No. Only the delay numbers are rewritten; every frame’s picture is copied from your file as it was stored, colour table included. The file stays the same size, give or take a few bytes.

Why is 3× not three times as fast

Frames that already play fast reach the 20 ms floor. A 30 ms frame at 3× would be 10 ms, which browsers show as 100 ms — slower, not faster. Those frames are held at 20 ms, and the line under the result gives the speed the GIF actually has.

Can I change the timing of one frame

Not on this page. Every frame is changed by the same factor, so the rhythm of the animation stays as it was.

Related specs

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