Property ROI calculator
The three figures to compare flats: gross yield, net yield and the return on the cash you put in (cash on cash), with the mortgage and yearly costs.
How much does this flat return?
Before tax and with the flat let all twelve months; the full calculator adds your region's income tax and the empty months.
- Running costs€1,50015%
- Interest€3,55535%
- Loan you pay back (still yours)€3,27332%
- You keep (cash flow)€1,87118%
| Purchase price | €150,000 |
| Purchase costs | €15,000 |
| Refurbishment and furniture | €5,000 |
| Total investment | €170,000 |
| Yearly rent | €10,200 |
| Yearly costs | − €1,500 |
| Mortgage payments (25 years) | − €6,829 |
| Yearly cash flow | €1,871 |
| Cash you put in | €50,000 |
| ROI counting what you repay on the loan | 10.3% |
Before tax and with no empty months: the full calculator counts them, with your region's income tax, and adds the IRR.
Indicative estimate. Not financial or tax advice.
Next: the full study of your flat
Find flats that already pay
Draw a circle on the map and we rank the flats for sale in the area by return, with the estimated rent of each one based on the rents around it.
What a full study looks like
The analysis of a flat from start to finish: detailed taxes, a 10-year projection, sale scenarios, sensitivity and the IRR. With these figures:
- IRR over 10 years
- 11.5%
- Monthly cash flow
- €169
- Net yield
- 5.3%
The full calculator
Your flat with everything: the transfer tax of your region, the mortgage, costs, empty months and income tax. Free and without signing up: the verdict, cash flow and return.
What property ROI is
ROI (return on investment) tells you how much the money you put in gives back each year. For a buy-to-let flat there are three figures, and each one is for something different.
Gross yield
Yearly rent ÷ purchase price. It is the one in the listings: quick to compare, but it counts neither purchase costs nor yearly costs. Below 5% gross, with a mortgage, a flat rarely pays for itself.
Net yield
(Yearly rent − yearly costs) ÷ total investment. The total investment adds the purchase costs (transfer tax, notary, registry) and the refurbishment to the price. It is the one that really describes the flat.
Return on the cash you put in (cash on cash)
Yearly cash flow ÷ money out of your pocket. With a mortgage it is the one that matters: it compares what the flat leaves you each year with the deposit and costs you have put in.
The part of the payment that repays the loan is not lost: it is wealth. That is why the calculator gives a second figure that counts it.
What is a good return
It depends on the city: with official data, the gross yield of the provincial capitals ranges from 3% in Madrid to almost 6% in Lleida. See your city.
What ROI leaves out
Taxes, appreciation and the sale. That is what the IRR is for: it brings everything together over the years. See a full study with the IRR.
Reviewed on 10 October 2026
Frequently asked questions
How is the ROI of a flat calculated?
Yearly cash flow (rent minus costs and mortgage payments) divided by the money you put in (deposit, purchase costs and refurbishment).
What is the difference between ROI and gross yield?
Gross yield only looks at rent and price; ROI looks at what you keep after costs and the mortgage and compares it with what you have put in.
What is a good ROI on a buy-to-let flat?
As a guide, with a mortgage, a return on the cash you put in of 5–8% a year before tax is already good in Spain; below 3%, the risk outweighs the gain.
Why can ROI be lower with a mortgage than buying outright?
Because each payment repays part of the loan: that money leaves your pocket but it is not a cost, it becomes paid-off flat. That is why it is worth looking at the IRR too.
What is the net yield of a rental?
What remains after yearly costs (service charges, property tax, insurance, maintenance) over everything invested. It is usually 2 to 3 points below the gross yield.
Indicative estimate. Not financial or tax advice.