Use ROI = (benefits − costs) / costs × 100, then be honest about both sides. Benefits are time saved, calculated as (manual time − automated time) × tests × runs, plus production defects avoided. Costs must include tooling, infrastructure, training and, above all, ongoing maintenance. One vendor example: 250 hours to build tests that save 20 manual hours a week pays back in about 13 weeks. Record baselines first (manual regression hours, escaped defects), and present pessimistic, realistic and optimistic scenarios, because leaders trust a range more than a single number. Vendor blogs also claim production defects cost 10 to 30 times more to fix, which is widely repeated but vendor-reported here.

Sources: Ranorex, Testsigma, Keploy