Most firms calculate automation savings the same way:
Time saved × hourly rate × frequency = annual savings.
That math isn’t wrong. It’s just incomplete. It misses the variable that often pushes the answer 30% higher: who does the task afterward.
The Standard Calculation
Take a monthly bank reconciliation. A senior accountant bills at $125/hour and spends 90 minutes per client. Across 40 clients, that’s 60 hours a month — $7,500/month, $90,000/year.
You evaluate an automation that drops the time to 15 minutes per client. Same person, same rate:
40 clients × 12 months × 0.25 hours × $125 = $15,000
Annual savings: $75,000. Worth doing. Sign it off.
But you’ve just left money on the table.
The Variable Almost Everyone Skips
After the automation, the remaining 15 minutes per client isn’t “do the reconciliation.” It’s “spot-check what the automation did and approve.” That’s not senior-level work. A junior at $50/hour can run that step every time.
Re-run the math with the right rate on the post-automation side:
40 × 12 × 0.25 × $50 = $6,000
Annual savings: $84,000 — not $75,000. The extra $9,000 didn’t come from saving more time. It came from the senior’s hour flowing into work that actually requires their judgment instead of into work the system now does for them.
The General Form
The full savings formula has two rates, not one:
Total annual savings = (X × Tbefore × Rbefore) − (X × Tafter × Rafter)
Where X is the number of times the task runs per year, T is time per run, and R is the labor rate. The mistake almost every spreadsheet makes is setting Rafter = Rbefore.
Once a task becomes “review and approve” instead of “execute,” the rate column has to change with it. Five minutes of click-to-approve is not senior-level time, even if a senior is currently doing it.
Why This Changes What You Can Spend
The reason it matters in practice: this is the number that sets your automation budget.
At $84,000/year saved, a three-year payback window justifies up to $252,000 of build and run cost. A five-year window: $420,000.
At $75,000/year — the version where you ignored the rate shift — those numbers drop to $225,000 and $375,000. That’s a $45,000–$70,000 gap on a single workflow, and it’s often the difference between “we can build this properly” and “we cut corners and lived with it.”
How to Size It Correctly
When you’re scoping any automation:
- Count the task as it runs today — minutes per run, runs per year, current labor rate.
- Define what’s actually left afterward — usually a quick review, an exception handler, or nothing at all.
- Match the rate to the remaining work, not the title of whoever happens to do it.
- Multiply through both sides — the gap between (Tbefore × Rbefore) and (Tafter × Rafter) is your real savings.
- Set your build budget as savings × payback years.
The firms that get the most out of automation aren’t the ones with the most exotic tech. They’re the ones who size the prize correctly — and that means counting both the time and the tier.