Before you approve the change, commit the capital, or sign off the business case - does the project actually pay back, and when? Enter your costs and benefits and get payback period, ROI and NPV instantly.
Not a finance specialist? Every term used below - CAPEX, OPEX, payback, NPV, ROI, discount rate, the realisation filter - is explained in plain English with an example in the glossary at the bottom of this page. All figures should be entered excluding VAT (net).
The basics, for your own reference and for the PDF you print or save.
Year 1 is the point the spend starts (equivalent to "Year 0" in formal DCF terms) and is not discounted - so "3 years" shows exactly three columns and "5 years" shows five.
Common categories are pre-filled - rename, delete or add rows freely. Tag each row CAPEX (one-off capital spend) or OPEX (ongoing running cost); see the glossary if a cost changes type over time.
| Cost item | Type | Yr 1 | Yr 2 | Yr 3 | Yr 4 | Yr 5 | |
|---|---|---|---|---|---|---|---|
| Total costs |
Common benefit types are pre-filled - rename, delete or add rows freely. Be honest about which year each benefit actually lands.
| Benefit driver | Yr 1 | Yr 2 | Yr 3 | Yr 4 | Yr 5 | |
|---|---|---|---|---|---|---|
| Total benefits |
Optional: if benefits typically under-deliver against plan in year one, apply an implementation realisation percentage below to discount them for that reason alone - separate from the discount rate, which accounts for the time value of money.
The option nobody costs. If you do not run this project, what does staying as you are actually cost - continued firefighting, workarounds, lost sales, a risk that eventually lands? Quantify it here and it is added in as an avoided cost, alongside the project's own benefits.
| Cost of not acting | Yr 1 | Yr 2 | Yr 3 | Yr 4 | Yr 5 | |
|---|---|---|---|---|---|---|
| Total cost of doing nothing |
No single correct discount rate. As a rough guide: public sector business cases typically use HM Treasury's Green Book rate of 3.5%. Private sector business cases most commonly default to 10%. Mid-market corporate WACC often runs 12–18%, and higher-risk or SME growth capital is frequently 15% or more.
| £ | Yr 1 | Yr 2 | Yr 3 | Yr 4 | Yr 5 |
|---|---|---|---|---|---|
| Total costs | |||||
| Total benefits (realised) | |||||
| Cost of doing nothing (avoided) | |||||
| Net cash flow | |||||
| Cumulative cash flow | |||||
| Cumulative discounted cash flow |
Costs are usually the estimate most likely to move. This flexes total cost up and down and holds benefits and the cost of doing nothing steady, so you can see how much the result actually depends on getting the cost estimate right.
| Costs -15% | Current costs | Costs +15% | |
|---|---|---|---|
| Payback | |||
| NPV | |||
| ROI |
Not everyone building a business case is a finance specialist. Click any term below.
CAPEX (capital expenditure) buys or creates something that will be useful for more than a year - usually a one-off cost. OPEX (operating expenditure) is the ongoing cost of running and keeping it useful. Like a car: the purchase is CAPEX; the insurance, fuel and servicing are OPEX. The Type you choose applies to the whole row, every year - if the same cost genuinely changes type over time (a licence capitalised in Year 1, then billed as an ongoing OPEX subscription from Year 2), split it into two rows rather than trying to change the type partway through one.
How long it takes for the money coming in, or saved, to add up to more than the money spent. If something costs £100,000 and saves £40,000 a year, it pays back in 2.5 years. The simplest, most intuitive number in this tool.
The same idea, adjusted so money arriving in future years counts for slightly less than money today (see Discount rate below). Always a little slower than the simple payback figure, and a more honest one.
Every pound of cost and benefit over the life of the project, added up in today's money. A positive NPV means the project is worth more than it costs once you account for the time value of money. A negative NPV means it isn't - even if the payback period on its own looks fine.
The total benefit as a percentage of the total cost, across the whole period. 200% ROI means you got back three times what you put in: your money back, plus double on top.
The percentage used to adjust future money into today's money, because a pound next year is worth a little less than a pound today. There is no single correct figure - see the guidance next to the field above.
A blunt but honest adjustment. Benefits on paper rarely land in full - set this below 100% if you want to be conservative about how much of the planned benefit will actually show up. Left at 100%, every planned benefit is assumed to land in full - worth a deliberate decision, not a default left unchecked.
What carrying on as you are actually costs - continued workarounds, lost productivity, a risk that eventually lands - even though nobody usually puts a number on it. Optional, but often the figure that changes the decision.
How many years into the future the numbers cover. Year 1 is the point the spend starts (equivalent to "Year 0" in formal DCF terms) and is not discounted - so "3 years" shows exactly three columns and "5 years" shows five. 3 years suits a quick, tactical project; 5 years is the more typical span for a full business case.
A machine costs £100,000 to buy (CAPEX) plus £10,000 a year to run (OPEX). It saves £40,000 a year in labour cost. Over 5 years: total cost £150,000, total benefit £200,000. Simple payback lands partway through year 3. At a 10% discount rate, NPV comes out positive - so on these figures, worth doing.
All figures should be entered excluding VAT (net) - the way most business cases are built. This tool does not handle VAT separately.
This is a self-serve calculation based on the figures you enter. It reflects your assumptions, not an independent audit of them - the numbers are only as good as what goes in. If you'd like a second pair of eyes on the business case before it goes to governance, I can help.
Read the thinking behind CAPEX/OPEX: Capex Buys the Car. Opex Keeps It Moving.
Also free: the Programme Health Checker, the MoSCoW Prioritisation Matrix, or the full set of tools.