What counts as a good ROI?

It depends on the sector, the risk and the time frame. As a rough guide, ROI should comfortably exceed what a low-risk alternative would earn over the same period, plus a premium for the risk taken. A positive but very low ROI may not justify the effort or the uncertainty.

What is the difference between ROI and operating margin?

Operating margin measures how much of each euro of revenue is left after operating costs, without taking the initial investment into account. ROI, by contrast, compares the final result with the capital invested. A project can have a high margin and still a low ROI if the investment is very large.

Yes. A negative ROI means revenue has not covered the costs and the investment in the period analysed. It does not always mean the project has failed: many investments have a loss-making first year and become profitable later, so it is worth assessing them over several periods.

Should I include VAT in the figures?

If your business can recover input VAT, the usual approach is to work with figures excluding VAT, because the tax is neither real income nor a real cost. If you cannot recover it, for example in exempt activities such as many healthcare or education services, the VAT you pay is part of the cost and should be included.

How should I read the payback period?

It shows how many months it would take to recover the investment if the monthly cash flow of the period analysed (revenue minus operating costs, divided by the months entered) stayed constant. It is a simple payback measure: it does not account for the time value of money or for changes in future results. If costs equal or exceed revenue, the calculator indicates that the investment is not recovered with that cash flow.

Can it help me decide whether to borrow?

It is a useful first filter, but when the investment is financed with a loan you should include the interest among the costs and assess the month-by-month impact on cash flow. For significant operations, our team can help you prepare a viability plan with several scenarios and their tax implications.

ROI & Investment Return Calculator for Spanish Businesses

Return on investment (ROI) measures how much profit each euro invested in a project, a campaign or the purchase of an asset generates. This calculator works out ROI, operating margin, monthly cash flow and the payback period from four inputs: the initial investment, the revenue generated, the operating costs and the length in months of the period analysed. If that period is not a year, it also shows the annualised ROI. It is a quick way to compare alternatives before committing resources.

What ROI is and what it is used for

ROI is a profitability indicator that relates the result achieved to the capital needed to achieve it. It is expressed as a percentage: an ROI of 25% means that, as well as recovering the amount invested, the project has generated a profit equal to a quarter of the investment.

Its main strength is simplicity. It puts very different decisions on the same scale, such as opening a second premises, replacing machinery, launching an advertising campaign or rolling out management software, so you can prioritise those that return the most for every euro committed.

How it is calculated: the formulas behind the tool

The tool works with amounts for the same analysis period, whose length you enter in months, and applies these formulas:

Operating costs are the expenses the project generates once it is up and running (raw materials, dedicated staff, commissions, maintenance or advertising), whereas the investment is the initial outlay needed to get it started; that is why it should not be included in costs. Keeping the two clearly separate is key for the result to make sense. The payback period is calculated using the cash flow before deducting the investment, since subtracting it from the flow would count it twice, and it is only shown when that flow is positive: if costs equal or exceed revenue, the investment is never recovered.

Net cash flow for the period = revenue generated − operating costs.
Net profit after recovering the investment = net cash flow − initial investment.
ROI (%) = net profit / initial investment × 100.
Operating margin (%) = (revenue − operating costs) / revenue × 100.
Monthly cash flow = net cash flow / months in the period; payback period (months) = initial investment / monthly cash flow.
Annualised ROI = (1 + ROI)^(12 / months) − 1, shown when the period analysed is not 12 months.

Worked example

A physiotherapy clinic invests €10,000 in diagnostic equipment. During the first year, the new services it offers with it generate €15,000 in revenue and €3,000 in associated costs, covering consumables, maintenance and part of the staff's time.

The net cash flow for the year is 15,000 − 3,000 = 12,000 euros and the net profit after recovering the investment is 12,000 − 10,000 = 2,000 euros, so the ROI is 2,000 / 10,000 = 20%. The operating margin of the new business line is (15,000 − 3,000) / 15,000 = 80%, showing that the services are highly profitable once the investment is covered. With a 12-month period, the monthly cash flow is 1,000 euros and the calculator estimates a payback period of 10,000 / 1,000 = 10 months. If the same figures related to a 6-month period, the ROI would still be 20%, but the annualised ROI would rise to 44% and the investment would be recovered in 5 months.

The figures are best read together. A high operating margin with a moderate ROI usually means the initial investment is large relative to the revenue for the period, and that cumulative returns will improve if the activity continues in subsequent years without further outlays.

ROI, tax and other complementary indicators

The ROI shown by the tool is a pre-tax figure. The profit that is ultimately available depends on taxation: for a company, Corporation Tax, with a standard rate of 25% and reduced rates for smaller and newly created businesses; for a sole trader, personal income tax (IRPF) at their marginal rate. In addition, if the investment is an asset used over several years, it is not deducted for tax purposes all at once but through annual depreciation in line with the official tables, except in specific cases where accelerated or free depreciation is allowed.

For bigger decisions it is advisable to complement ROI with other indicators:

Annualised ROI, to compare projects of different lengths on a like-for-like basis; the calculator shows it when the period entered is not 12 months.
Net present value (NPV) and internal rate of return (IRR), which take into account when cash flows occur and the cost of money.
ROE, which measures the return on equity and is useful when part of the investment is financed with debt.
Break-even point, to find out the minimum sales volume that covers all costs.

Common mistakes when measuring profitability

The ROI formula is simple, but its usefulness depends on the quality of the data. These are the errors that most distort the result:

Leaving out indirect costs, such as staff time, insurance or financing interest, which artificially inflate ROI.
Mixing periods: comparing one quarter's revenue with annual costs, or a six-month project with a three-year one without annualising.
Counting revenue that would have been earned anyway without the investment. ROI should measure the incremental effect of the project.
Confusing operating margin with profitability: an 80% margin does not guarantee the investment will be recovered if sales volume is low.
Accepting forecasts without testing them. It is sensible to calculate at least a cautious scenario and an optimistic one.

Content written and reviewed by the advisory team at Vertice Gestión Empresarial. Results are for guidance only and do not replace professional advice.

ROI and Profitability Calculator