Business Case Financial Calculator
Prove your improvement project pays before you ask for funding. Enter the investment, the running costs, the savings and the risk profile, then read back NPV, IRR, payback, profitability index and a risk adjusted viability score.
🎯 What this calculator does
This tool builds a discounted cash flow model for a single improvement project. You enter what the project costs to build, what it costs to run, what it returns each year and how confident you are in those returns. The calculator converts that into the five numbers a finance approver asks for: net present value, return on investment, payback period, internal rate of return and profitability index.
Most Six Sigma business cases fail at the funding gate for one reason. They quote gross annual savings and stop there. A finance team wants the money in present value terms, net of tax, net of the cost to run the new process, and adjusted for the chance the project misses its target. This calculator does all of that from your raw inputs.
It also runs a sensitivity check. Move the benefit and cost sliders after you calculate and watch NPV shift. If a 20 per cent benefit shortfall wipes out your NPV, your business case is fragile and you need a wider benefit base before you present it.
📐 Every formula used
Net cash flow (year n) = (Annual benefits realised - Annual operating cost) x (1 - tax rate) + depreciation tax shield
Depreciation tax shield = ((Initial investment - Salvage value) ÷ Project years) x Tax rate
NPV = Sum of discounted net cash flows plus discounted salvage, minus the initial investment
ROI = (Total net cash flow + Salvage - Initial investment) ÷ Initial investment x 100
Payback period = the point where cumulative net cash flow crosses zero, interpolated to a decimal year
IRR = the discount rate that sets NPV to zero, solved by bisection
Profitability index = Present value of all future net cash flows ÷ Initial investment
Risk adjusted NPV = NPV x Success probability x Risk factor (0.95 low, 0.85 medium, 0.70 high)
📋 How to use it
- Open the Calculator tab and load a sample dataset to see the model behave. Manufacturing shows a strong case. Contact centre automation shows a weak one.
- Enter your initial investment. Include capital, consulting, software licences, training and the internal labour cost of the project team.
- Enter the annual operating cost of the new process. New software subscriptions, extra maintenance, extra headcount, calibration and audit time all count.
- Set the project duration to the period over which you will claim benefits. Three to five years suits most process improvement work. Use the asset life for capital projects.
- Enter annual cost savings and annual revenue increase separately. Savings are money you stop spending. Revenue increase is new margin, so enter the margin, not the top line.
- Set the discount rate to your organisation's hurdle rate or weighted average cost of capital. If nobody can tell you, 8 to 12 per cent is a fair working range in Australia.
- Set the benefit realisation delay in months. This is the gap between spending the money and the savings appearing in the ledger. Be honest here. It moves NPV more than people expect.
- Set the success probability and risk level, then click Calculate financial metrics. Read the verdict, then move the sensitivity sliders to test how fragile the case is.
📊 How to read the viability score
The calculator scores your business case out of 100. Points come from five weighted tests: NPV against the investment size, IRR against your hurdle rate, payback speed against project life, profitability index and risk adjusted NPV.
| Score | Verdict | What it means | What to do |
|---|---|---|---|
| 80 to 100 | Strongly viable | Returns clear the hurdle rate with room to spare and survive the risk adjustment. | Submit for approval. Lock the benefit baseline before you start. |
| 60 to 79 | Viable with conditions | The case works but one metric is soft, usually payback or risk adjusted NPV. | Approve with a stage gate. Review benefits at the halfway point. |
| 40 to 59 | Marginal | Value is positive but thin. A small benefit shortfall turns it negative. | Rework the scope. Cut the investment or widen the benefit base. |
| 0 to 39 | Not viable | The project destroys value at your current cost of capital. | Do not fund as scoped. Look for a smaller pilot or a different problem. |
⚠️ Common mistakes
- Counting soft savings as hard savings. If the saved hours do not leave the roster or move to billable work, finance will not accept them.
- Leaving out the annual operating cost. A project that saves 200,000 dollars a year and costs 90,000 dollars a year to run is a 110,000 dollar project.
- Setting the benefit delay to zero. Almost no process change delivers full benefit from day one. Three to six months is normal.
- Entering gross revenue instead of margin. A 500,000 dollar revenue lift at 12 per cent margin is worth 60,000 dollars, not 500,000 dollars.
- Using a discount rate you invented. Ask finance for the hurdle rate. Using 5 per cent when the business uses 12 per cent will get your case rejected on the spot.
💡 Pro tips
- Run the model three times. Best case, expected case and worst case. Present the expected case and show you have tested the other two.
- Set the benefit slider to 80 per cent before you present. If NPV stays positive there, your case survives a 20 per cent shortfall and you can say so with confidence.
- Get the finance business partner to review your inputs before the steering group, not after. It converts an argument into a rubber stamp.
- Split one time benefits out from recurring benefits. Approvers discount one time benefits heavily and they are right to.
- If payback runs past year three, look for a phased scope. A smaller first phase that pays back in twelve months buys you the credibility to fund phase two.
- Keep the exported workbook. Twelve months in, rerun the model with actuals and compare. That single habit builds the trust that gets your next project funded.
🔎 Where this fits in DMAIC
This is a Define phase tool. The business case sits in the project charter and sets the financial target the project is held to. You build it before the tollgate, using baseline data from the Measure phase of an earlier project or from your existing process metrics.
It returns in the Improve phase when you compare solution options. Run the model once for each option and fund the one with the best risk adjusted NPV, not the one with the largest headline saving. It returns again in Control, where you rerun it with twelve months of actuals to verify the benefit was real.
📥 Load a sample dataset
Load an industry example to see how the model behaves, then replace the numbers with your own. The contact centre example is deliberately weak so you can see a failed business case.
🧾 Project inputs
Enter your own figures in whole dollars. Every field feeds the cash flow model directly.
Investment and costs
Benefits and savings
Financial parameters
Risk assessment
⚠️ No analysis yet
Enter your project figures in the Calculator tab and click Calculate financial metrics to generate your business case.
What a business case financial calculator does
A business case financial calculator converts a project proposal into the language finance uses. It takes the money you spend, the money you save and the timing of both, then discounts every future dollar back to today. The result tells you whether the project creates value at your organisation's cost of capital, or destroys it.
Six Sigma teams need this because a defect reduction target is not a funding argument. Cutting scrap from 8 per cent to 2 per cent means nothing to a chief financial officer until it becomes a dollar figure, net of tax, net of the cost to sustain the change, and set against the capital tied up in the project.
How to calculate NPV for an improvement project
Net present value takes each year of net cash flow and divides it by one plus the discount rate raised to the power of the year number. Add those discounted figures together, add the discounted salvage value, then subtract the initial investment. A positive NPV means the project earns more than your hurdle rate.
Net cash flow is not the same as gross savings. Subtract the annual operating cost first, then apply tax, then add back the depreciation tax shield if the investment is capitalised. Teams that skip those three steps overstate NPV by 30 to 40 per cent, which is why finance rejects the case at the first review.
What payback period is acceptable
Most Australian organisations want process improvement projects to pay back inside two years and capital projects inside four. The calculator interpolates the crossing point, so a payback of 2.4 years means the cumulative cash flow turns positive four tenths of the way through year three.
Payback ignores everything that happens after the crossing point. Use it as a liquidity check, not a value measure. A project with a fast payback and a low NPV returns your money quickly and then stops earning.
Reading the four viability bands
Strongly viable, 80 to 100
Returns clear the hurdle rate with margin and survive the risk haircut. Submit the case and lock the benefit baseline before the project starts.
Viable with conditions, 60 to 79
The case works but one metric is soft. Approve with a stage gate and a benefit review at the halfway point.
Marginal, 40 to 59
Value is positive but thin. A modest benefit shortfall turns it negative. Rework the scope before you present it.
Not viable, 0 to 39
The project destroys value at your current cost of capital. Look for a smaller pilot or a higher value problem.
Why risk adjusted NPV matters
Raw NPV assumes you hit every benefit in full and on time. Few projects do. The calculator multiplies NPV by your stated success probability and by a risk factor tied to the complexity of the change. A project with a 400,000 dollar NPV, a 60 per cent success probability and a high risk rating carries a risk adjusted NPV of 168,000 dollars.
Present both numbers. Showing the approver that you have already discounted your own case builds more credibility than any headline saving.
Frequently asked questions
What discount rate should I use?
Ask your finance team for the organisation's hurdle rate or weighted average cost of capital. If no rate exists, 8 to 12 per cent covers most Australian mid sized organisations. Higher rates apply to volatile industries and to projects competing with a strong alternative investment.
Should I include internal labour in the initial investment?
Yes, if the people are dedicated to the project or backfilled. Cost them at fully loaded rates including on costs. Leave out incidental time from staff who attend a workshop and return to normal duties.
What is the difference between NPV and ROI here?
NPV is a dollar figure that accounts for the time value of money. ROI is a percentage that ignores timing. NPV decides whether to fund. ROI communicates the scale of the return to people who dislike discounting.
Why is my IRR showing as not defined?
IRR only exists when the cash flow pattern crosses zero. If every year is negative, no discount rate can bring NPV to zero. That result is itself the answer. The project has no rate of return.
How do I use the sensitivity sliders?
Calculate first, then move the benefit slider to 80 per cent and the cost slider to 120 per cent. That combination is a realistic pessimistic case. If NPV stays positive, your business case survives normal execution slippage.
Can I export the results?
Yes. The calculator produces a branded four sheet Excel workbook containing a summary, your input data, the full year by year cash flow and the recommended actions.
