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Business Case Calculator

Take an initiative you need to justify right now. Enter what the rollout costs once, what it costs every year afterwards, and the benefit you expect per year. This page puts the three numbers side by side and shows how far your assumptions can be wrong before the case stops working.

3 numbers~2 minutesInstant resultFree
Everything up to go-live: development, integration, data preparation, rollout, training at launch.
€ one-off
What falls due every year from go-live onwards. This is the field missing from most business cases.
€ / year
What belongs in the running cost?

What belongs here: hosting and infrastructure, licences, and for AI initiatives also API, token and inference costs, support and maintenance, model and version updates, governance effort (sampling, audits, evidence), and a share of business-team time if someone looks after the system on an ongoing basis.

What does not belong here: one-off costs up to go-live. That goes in the field above. Training at rollout is project cost; training new joiners from year two onwards is running cost.

If you have no figure, make a rough estimate rather than leaving it out. A zero in this field is almost always wrong, and it shifts the result more than any imprecision would.

In euros, from go-live. Count time saved only where it genuinely turns into money.
€ / year
What counts as benefit?

Three kinds, in descending order of how well they can be backed up: cost avoided (a mistake that no longer happens demonstrably cost X), time saved and additional revenue. Be conservative on the last one, because reviewers attack it first.

The uncomfortable question about time saved: two person-days a week become a benefit only once someone decides what happens to that time: a vacancy goes unfilled, a backlog gets cleared, an extra order is accepted. Without that decision the time quietly disperses into everyday work and shows up in no figure at all.

A year, not the first year. Enter the benefit in its steady state. The ramp-up during year one is deliberately left out here. The limits are shown below the result.

Over what period are you calculating?

The arithmetic is the easy part

What comes after is harder: describing the benefit so that it becomes measurable, having a baseline before you start, and proving after go-live how much of it actually arrived. That is exactly the course “Making the case”, which launches on 16 November 2026: making benefit measurable, taking a baseline, proving it after go-live.

Browse all courses →

Assumptions behind the calculation: project cost falls due at the start; running cost and benefit accrue evenly from go-live across the period. Nothing is discounted. Payback is the point at which the accumulated surplus of benefit minus running cost covers the one-off project cost.

This page claims no benchmarks. There is no reliable figure for what share of running cost is “normal” or what adoption rate would be “typical”. Both depend far too much on the initiative. Everything on this page is arithmetic on your own numbers.

Nothing you type leaves your browser: the calculation runs entirely on your device, with no server call and no form. Your figures are not stored anywhere.

Working out ROI and payback and what the number does not tell you

A business case is not proof; it is an assumption written down. The calculator takes three numbers (one-off project cost, annual running cost, expected annual benefit) and turns them into a payback period and a return. The value is not in the result but in the fact that the assumptions are on paper afterwards.

Business cases rarely fail on the formula. They fail on a missing number: the running cost. Many templates have no field for it at all, and a zero there shifts the result more than any imprecision on the benefit side.

The three inputs

One-off project cost
Everything up to go-live: development, integration, data preparation, rollout and the training that comes with it.
Annual running cost
What recurs every year from go-live: hosting, licences, for AI work also API and inference cost, support, model updates, governance effort and a share of the time spent looking after it. The field most templates are missing.
Expected annual benefit
In euros, at steady state. Avoided cost is the easiest to defend, additional revenue the hardest. Time saved counts only once someone has decided what to do with it.

Frequently asked questions

How do you calculate the ROI of a project?

Benefit minus cost, divided by cost. The deciding factor is the time horizon: over one year an initiative with heavy setup cost looks poor, over five years it often looks good. The calculator shows both side by side so the choice of horizon stays visible instead of quietly setting the result.

What is the payback period?

The point at which cumulative benefit exceeds cumulative cost. It is the more honest figure, because it does not depend on how long you keep counting.

What belongs in running cost?

Hosting and infrastructure, licences, for AI work API, token and inference cost, support and maintenance, model and version updates, governance effort and a share of the time spent looking after it. What does not belong is anything that happens once before go-live — rollout training is project cost, follow-up training from year two is running cost.

Does saved working time count as a benefit?

Only to the extent it turns into money. Two person-days saved per week become a benefit once someone decides what to do with that time: a role is not backfilled, a backlog is worked down, an additional order is accepted. Without that decision it lightens the load, but it is not a result.

Is the calculator enough for an investment proposal?

For the pre-check, yes — it shows whether a full proposal is worth the effort at all. For the proposal itself it lacks discounting, a first-year ramp and risk scenarios. Those limits are shown directly under the result, so the number does not promise more than it can support.

How do I build a business case that the finance department will accept?

Finance accepts a benefit it can check. That takes three numbers with a source: one-off project cost, annual running cost and annual benefit, split into avoided cost, time saved and additional revenue. Payback and ROI follow from them. Add a baseline from before the project and a statement of how far the assumptions may be off. Example with freely chosen, undiscounted figures: 240,000 € one-off, 50,000 € running and 200,000 € benefit a year give payback after 1.6 years and 54 % ROI over three years. The case tips if the benefit falls below 130,000 € a year, which is 35 % under the assumption. That limit belongs in the template, not only the result.

Further reading

Business Case Calculator — work out ROI and payback for free — Agile Forge