Work out automation time saved instantly with clear inputs, formula shown and shareable results.
Automation savings are volume times the per-task time reduction, converted to hours and priced at the loaded hourly cost. The subtlety is the residual time after automation: review, exception handling and correction rarely fall to zero, and quoting the full before-time as saved is the most common way automation business cases become fiction.
Time saved
saved minutes = tasks x (before - after); hours = minutes / 60; cost saved = hours x loaded hourly cost
Only if the capacity is redeployed or headcount changes. Otherwise the benefit is extra output or reduced backlog, which should be described as such rather than as a cost reduction.
Everything the human still does: reviewing output, correcting errors, and handling the cases automation rejects. Measure it on a pilot rather than assuming it is near zero.