MatchRate is an After Effects script for extending a layer property’s animation at the same rate.

Instructions
- Select two keyframes and click ‘Get Rate.’ The rate of the animation will load.
- Select the layer whose animation you want to change (it can be the same layer)
- Select the keyframe you want as the start of your new animation.
- Move the playhead to where you want the animation extended.
- Click ‘Apply Rate’ and the script write a new keyframe to the layer at the matched rate.*
* You can also choose which property dimension you’d like to target and at what percentage of the rate you’d like to apply the new keyframe.