Most common calculation of Automation ROI:
Savings = Manual execution time * no. of times expected to run
Except, this doesn’t give any real value..
These tests we are calculating under time ‘saved’, mostly never get tested!
A lot of times testers just try to fit in whatever they can in the given time duration, and many of these tests just cannot be done
The real value of automation is the quick feedback you get
Instead of regression issues being reported weeks later, devs get instant feedback and takes a lot less to fix the issue.
Automation does save effort, but not in the way we usually calculate it.
Details on this and other ROI calculation aspects in the linked blog post