How to determine the length of a .gif animation in milliseconds

Question

Is there an easy way to figure out approximately how long a .gif image takes to play one time in Javascript?

Answer 1

I tried ImageMagick identify but it didn't give me the correct duration.

I found another reliable way using ExifTool

exiftool -Duration image.gif

It will print out the duration in seconds:

Duration : 0.48 s