Calculate the real yield of a buy-to-let flat
Enter purchase price, financing, regional transfer tax (ITP), expected rent and annual costs. Calculate gross yield, net yield, monthly cash flow, cash-on-cash, ROCE and equity required before you buy. Prefer a step-by-step guide? Read how to calculate rental yield on a flat.
Not just price
Includes ITP, purchase costs, renovation, furniture and financing.
Not just rent
Deducts council tax (IBI), insurance, service charges, maintenance and vacancy.
Not just yield
See whether the deal generates cash or relies on capital growth.
1. Purchase inputs
Estimated ITP applied
6%
Indicative general rate.
2. Financing and income
3. Annual costs
What does each result mean?
These metrics help you see whether a property can be a sound investment — or whether, despite looking profitable, it needs too much equity, generates little cash flow, or leans too heavily on future appreciation.
Equity required
The cash you must put in to buy: deposit, taxes, fees, renovation, furniture and other unfinanced costs.
Monthly cash flow
What remains each month after collecting rent, paying estimated costs and deducting the mortgage payment.
Gross yield
Compares annual rent with total purchase cost. Useful as a first filter, but it ignores many costs and the effect of financing.
Net yield before mortgage
Takes rental income minus annual costs such as IBI, insurance, service charges, maintenance and vacant months.
Cash on cash
Measures the annual return on the cash you actually invested after costs and the mortgage.
ROCE
Measures return on capital employed before financing. Useful for comparing deals with different leverage.
Estimated ITP
Estimated property transfer tax based on the autonomous community and the use of the home.
Total purchase cost
Sums purchase price, ITP, notary, land registry, mortgage costs, renovation, agency fee and furniture.
Step-by-step guide
Want to understand the formulas before you buy?
We have prepared a guide to calculate gross yield, net yield, cash flow and cash-on-cash for a buy-to-let flat, with examples and common mistakes.
Learn the full calculation
Read the yield guideGross yield is not real yield
Gross yield can work as a first filter, but it should not drive a purchase decision. A property deal needs recurring costs, taxes, vacancy, maintenance, financing and contingencies deducted.
Cash flow is the stress test
An investment can look attractive on paper and still strain liquidity every month. Cash flow shows whether the deal holds when costs, vacant months or a demanding mortgage payment appear.
You are not buying a flat — you are buying a deal
The asset can be good and the deal still poorly structured. Price, debt, rent, costs, tax, liquidity and exit should be analysed together before you sign.
Costs many investors overlook
Many flats look profitable because they are modelled too simply: purchase price versus monthly rent. A real property investment has more layers. Before buying, review fixed costs, variable costs, taxes, financing and a safety buffer.
Scenarios you should stress-test before buying
A sound investment should not work only in the perfect scenario. Before buying, check what happens if letting takes longer, achieved rent is below expectations, rates rise, or renovation costs more than planned.
Flat vacant for 1–2 months
The mortgage, IBI, service charges and insurance still run even with no rent.
Rent 10% lower
The listing may be optimistic. Achieved rent at completion can cut yield sharply.
Rate rise
If financing becomes more expensive, cash flow can flip from positive to negative.
More expensive renovation
A €5,000 or €10,000 overrun changes equity required and real return.
Premium report
Want to know if this investment holds under real scenarios?
The calculator gives a first estimate. The Premium Report analyses vacancy, rate rises, rent falls, extraordinary costs, cash flow, net yield, deal risks and an indicative comparison versus the S&P 500.
✓ Flat vacant 1–2 months
✓ Rate rise +1% and +2%
✓ Net yield and cash flow
✓ Deal risk map
✓ Equity required and cushion
✓ Final investment verdict
You may also find useful
Rental yield guide
Learn to calculate gross and net yield, cash flow and cash-on-cash step by step.
Madrid ITP calculator
Estimate ITP for a used home in the Community of Madrid.
Madrid purchase costs
Review taxes, notary, land registry, admin fees, valuation and other costs.
How much cash do I need to buy
Estimate deposit, taxes, fees and a cushion before you sign.
These can also help
Frequently asked questions
Common questions on property yield
How do you calculate the yield on a rental flat?
A basic approach compares annual rent with total purchase cost. For a more realistic analysis, deduct costs, vacancy, taxes, financing and maintenance.
What is the difference between gross and net yield?
Gross yield uses annual rent versus purchase cost. Net yield deducts costs such as IBI, service charges, insurance, maintenance and vacant months.
What is monthly cash flow?
The cash left each month after collecting rent and paying estimated costs and the mortgage payment. It is a key measure of whether the deal holds.
What is cash on cash?
Cash-on-cash measures the annual return on the cash you actually put in, after financing, costs and cash flow.
Why can a profitable investment have negative cash flow?
Because it may show an acceptable theoretical yield before financing, while the mortgage payment, costs, vacancy or taxes consume monthly cash.