Methodology: how the calculator works

By Lawrence Goh, Director, Autonex Pte Ltd · Updated 23 Oct 2026

The AI Automation ROI calculator is deliberately simple and transparent. This page sets out every formula and assumption so you can check the results, adapt them, or rebuild them in a spreadsheet.

Inputs

Input	Meaning	Default
People	Number of people who do the selected tasks	5
Hourly cost	Fully loaded cost of one hour of their time	40
Working weeks	Weeks worked per year after leave and holidays	46
Task hours	Hours per person per week on each selected task	13 in total
Time saved %	Reduction in time on those tasks when AI-assisted	35%
Adoption %	Share of people who actually use the tool	80%
Ramp-up	Months during which benefits are counted at 50%	2
Setup cost	One-off cost: design, integration, data cleanup, training, pilot	5,000
Licence per user	Monthly tool cost per active user	30
Other running costs	Monthly API usage, maintenance, support	150

Formulas

Active users = ceil(people × adoption) Hours saved / week = Σ task hours × people × time saved × adoption Hours saved / year = hours saved per week × working weeks Value of time / yr = hours saved per year × hourly cost Running cost / yr = (licence × active users + other running costs) × 12 Year-1 value = value of time × (12 − 0.5 × ramp-up months) ÷ 12 Year-1 ROI = (year-1 value − running cost − setup) ÷ (running cost + setup) Years 2–3 net = value of time − running cost (each year) 3-year net value = year-1 net + year-2 net + year-3 net Payback = first month in which cumulative (monthly value − monthly running cost) ≥ setup cost, with monthly value halved during ramp-up

Key assumptions and limits

Time is valued at cost. The calculator values saved hours at what they cost the business. It does not estimate extra revenue, and saved time only becomes a financial gain if it is redeployed.
Savings apply to selected tasks only, not to whole jobs. This matches the research: large gains on specific tasks, modest gains across whole jobs.
Flat over time. Years two and three repeat the year-one run rate. In practice benefits may grow as processes improve, or fade if tools are not maintained. Prices and wages are not inflated.
No discounting. Values are not discounted to present value. For a three-year horizon at typical discount rates this changes results modestly; use a spreadsheet if you need NPV.
Quality effects are excluded. Fewer errors or faster customer response may add value; more errors may subtract it. Neither is in the number.
No tax, financing or depreciation effects.

Why the default time savings are 35%

Controlled studies of AI assistance on specific work tasks have found average gains of about 14% (customer support) to 25% (consulting tasks), with larger gains for less experienced workers, and a slowdown of 19% for experienced developers in one trial. Highly repetitive tasks — formatting, extraction, routine drafting — can see much larger savings. A moderate 35% default on targeted repetitive tasks, with 20% and 50% presets either side, reflects that range. The evidence is summarised in what the research says.

Privacy

All calculations run in your browser. Nothing you enter is sent to us. If you use "Copy link", your inputs are placed in the page address so the scenario can be shared.

Changes and corrections

We review the defaults when significant new research is published. If you think a formula or source is wrong, please tell us.

Sources

Lawrence Goh, Director, Autonex Pte Ltd. Lawrence designs AI and workflow automation for small and mid-sized businesses. About the author · How we write and check our guides