Render Time Calculator
Installation
Edit>Preferences>Add-ons>Install then select the Zip file
Usage
Enter the amount of time required to render a single frame, and the addon will automatically calculate the total time required for the entire animation.
In the advanced mode, you have the option to enter three separate time values. These time values do not necessarily have to correspond to the first, middle, and last frames of the animation. Instead, you can choose frames that exhibit the greatest deviation in rendering time.