The KeyBid ROI Calculator extension: a practical guide to analysing property listings

When you are looking for an apartment to run as a short-term rental, the first obstacle is not a shortage of listings but time: every promising listing calls for a calculation of revenue, costs and yield. The KeyBid ROI Calculator extension makes a first estimate for you, directly on the listing page, for apartments for sale on Storia, Imobiliare.ro and OLX. This guide shows you how to install it, how to read the figure correctly, how to use it in three concrete situations, what it cannot know and when the PDF report is worth buying, with information valid for version 1.2.0 in October 2026.

In brief

The extension costs nothing and works in Chrome and Firefox on desktop. On sale listings for apartments, studio flats, studios and penthouses on Storia, Imobiliare.ro and OLX, it shows an estimated annual yield and a colour-coded label.
The estimate is calculated in your browser from the listing's public data, with standard assumptions for seasonality and operating costs of 35–40%. Use it as a quick filter, not as a promise of income.
The figure is a net yield on the asking price: it does not include financing, transaction costs, furnishing or renovation.
The PDF report costs 49.99 lei for listings in Romania and €24.99 for listings in Greece and Spain, via the dedicated extensions. It breaks the estimate down into revenue, costs and seasons and arrives by email within minutes, with no account needed. It is not an ANEVAR valuation.
Legal checks remain your responsibility: seismic risk, the owners' association approval, neighbours' consent and the 7-room limit are not part of the estimate.

What the extension does and where it works

KeyBid ROI Calculator is a browser extension for Chrome and Firefox on desktop. The Romanian version works on Storia.ro, Imobiliare.ro and OLX.ro, and there are separate extensions for Greece (Spitogatos) and Spain (Idealista). When you open an eligible listing, the extension reads the public data on the page and displays a panel on the right-hand side of the screen with the estimated annual yield from short-term rental.

Since version 1.2.0, the panel only appears on properties suited to this type of rental. The estimate is built for apartments: for a house, a plot of land or commercial premises, costs and demand would be different, so the extension shows nothing.

The panel appears	The panel does not appear
On sale listing pages for apartments, studio flats, studios and penthouses	On rental listings, even for apartments
On Storia.ro, Imobiliare.ro and OLX.ro (Romanian version)	On houses, villas, land, commercial premises and other property types
A few seconds after the page loads	In search results lists: the panel only shows on each listing's own page

Installation and first analysis, step by step

Install the extension. On the KeyBid extensions page, choose the version for your browser, which takes you to the Chrome Web Store or to Firefox Add-ons. Installation costs nothing and requires no account.
Open a listing. Search as usual on Storia, Imobiliare.ro or OLX and open the page of an apartment for sale.
Read the panel. A few seconds after the page loads, the KeyBid panel appears with the estimated annual yield, a colour-coded label and a short note on the assumptions used: average occupancy and standard operating costs.
Decide whether you want the report. For listings that pass your first screening, you can generate the PDF report from the button in the panel. Payment is made on a secure Stripe page, with no account, and the report arrives by email.

What data the extension uses. According to its description in the extension stores, the extension only processes the public elements of the listing page, such as the price, floor area, title and public photo; it does not collect personal browsing data or track your activity. Report payments are processed by Stripe, and KeyBid does not store card details.

How to read the estimated yield

The figure in the panel is a net annual yield: the estimated income from short-term rental, after operating costs and taxes, measured against the asking price in the listing. The formula, which the PDF report also explains, is simple: annual net income divided by the property price, multiplied by 100.

The estimate starts from the sale price and usable floor area, the city and area (with dedicated multipliers for tourist markets such as Mamaia, Brașov, Cluj-Napoca and Bucharest), the property type, the seasonality of the Romanian market and typical operating costs of 35–40% of revenue. The colour-coded label shows at a glance where the result sits: green for the highest estimated yields, orange for average ones and red for modest ones.

What the figure leaves out matters just as much:

Financing. The yield is calculated as if you paid for the apartment in full. If you take out a mortgage, the interest comes out of your income, and the return on your own money can be much lower. With IRCC at 5.57% in the fourth quarter of 2026, plus the bank's margin, it is worth running the full calculation using the steps in our guide to financing and due diligence.
Entry costs. Notary fees, land registry costs, any agency commission, furnishing, equipment and renovation are not included.
The final price. The calculation uses the asking price, not the price you negotiate.
Changes in value. The rental yield does not include any rise in the apartment's price: the imobiliare.ro index showed a 6.0% year-on-year increase in September 2026. Nor does it include the risk of a fall.

Illustrative example: from the panel figure to the return on the money invested. Suppose a two-room apartment is listed at €120,000 and the panel shows an estimated yield of 7%, i.e. net income of about €8,400 a year. You negotiate the price down to €114,000 but spend €12,000 on furnishing, equipment and transaction costs, so the total investment is €126,000. If net income stays at €8,400, the return on the money actually invested is 6.7%, not 7%. If you also take out a loan, deduct the interest from the income before dividing.

How should you judge the result? Compare it with your alternatives: a deposit rate, the yield from a classic long-term let of a similar apartment in the same area and, if you borrow, the cost of the loan. Short-term rental takes more work and carries more risk than long-term letting, so set a minimum threshold in advance that includes a premium for the difference.

Three workflows with the extension

The same figure serves different purposes depending on where you are in the process. Here are three common situations:

Situation	What you do with the extension	What else you check
You are looking for an apartment and comparing dozens of listings	You go through 15–20 listings in your target area in a single session and note the estimated yield in a spreadsheet	Price per square metre, floor, year of construction, access to transport and attractions
You have 2–3 finalists before making an offer	You generate the PDF report for the finalists and use it in negotiations and in discussions with a partner	Market data for the area, the building's documents, your real costs
You already own an apartment and are considering short-term rental	You open comparable sale listings in the same area to see the order of magnitude of the yield	The classification requirements and the difference compared with long-term letting

1. Screening: from 20 listings to 3

Open the listings in your area of interest in a single working session and note, for each one, the link, price, floor area, price per square metre and estimated yield. Discard the listings below your threshold and keep 3–5 for checks. Use the estimate as an order of magnitude: a difference of a few tenths of a percentage point between two listings tells you little, whereas a gap of several percentage points is worth investigating.

2. Verification: before the offer

For your finalists, compare the estimate with the market. In KeyBid Puls you can see the prices of comparable listings in the zones on the map and the events that influence demand, while AirDNA data shows the city's average daily rate, occupancy and seasonality. We explain how to read them without fooling yourself in our guide to AirDNA and KeyBid Puls data. Then generate the PDF report for one or two finalists and work through the checks in our investor checklist.

3. Advisory work: when you work for others

Property managers and consultants use the extension to discuss options with a client on the basis of shared figures: the panel estimate for the first listings, the PDF report for the chosen apartment, and then data from the units they already manage, which shows how a similar apartment actually performs.

If you already own the apartment. Measure the yield against the apartment's current value, not the price you paid a few years ago. The money tied up in the apartment could be earning something else, and the right comparison is with the price you could sell it for today.

What the extension does not know

The estimate sees what the listing shows: the price, floor area, city and property type. Anything that does not appear in the listing still needs checking:

Seismic risk. Law No. 212/2022 prohibits renting out space in buildings classified in seismic risk class I, and Airbnb has started checking listings in such buildings. The verification steps are in our guide to seismic risk.
Classification requirements. Order No. 948/2026 requires the owners' association's approval and the consent of directly affected neighbours, and limits what you can classify as a private individual to 7 rooms and 14 places. The details are in our guide to Order 948/2026.
The apartment itself. Floor, view, lift, parking, noise and the condition of the finishes affect the nightly rate but are not part of the calculation.
The accuracy of the listing. If the floor area or price in the listing is wrong, the estimate will be wrong too. Compare the floor area with the land registry extract before making an offer.
Your real costs. Airbnb's single 15.5% fee plus a 15–25% management commission can together amount to 30–40% of revenue, before cleaning, utilities and consumables. If that is what your costs look like, redo the calculation with your own figures.
Your tax situation. The PDF report includes estimated taxes, but social contributions depend on your other income and on the number of rooms you rent out: see our 2026 tax guide.
Extreme seasonality. An annual figure hides the weak months. On the coast, a large share of revenue comes in July and August, as we show in our analysis of an apartment in Constanța and Mamaia.

The PDF report: what it contains and when it is worth it

The report starts from the yield shown in the panel and breaks it down into its components over five pages. The seasonal breakdown uses the area's seasonal profile from AirDNA data, where one is available.

Section	What you will find
Property	The listing photo, location, floor area, number of rooms, asking price and price per square metre, calculated from the actual floor area
Yield	The estimated annual yield from the panel and the calculation formula
Financial analysis	Average nightly rate, occupancy, occupied nights per year, gross revenue, operating costs, taxes and net income
Seasonality	Summer (June–August), winter (December–February), spring and autumn, with the occupancy, rate and estimated revenue for each period
Conclusion	Strengths and weaknesses, risk factors and limitations, a recommendation and steps you can take to increase the yield

The report costs 49.99 lei for listings in Romania and €24.99 for listings in Greece and Spain. You pay once per report, with no subscription and no account, and the report arrives by email within minutes.

Worth it for the finalists from your screening, before negotiating, and when you are talking to a partner, the bank or a property manager and need the figures on paper.
Not worth it for screening dozens of listings: that is what the panel estimate is for, and it costs nothing.
No substitute for a valuation: for a mortgage, the bank relies on a report from an ANEVAR-authorised valuer. Nor does it replace legal checks. The report itself states that it is generated automatically from publicly available data and KeyBid Puls algorithms and does not constitute financial or investment advice.

Common mistakes

Treating the estimate as a promise. It is a quick filter. The actual result depends on the final price, management, the season and the occupancy you achieve.
Choosing between two listings on the strength of a few tenths of a percentage point. With differences that small, the floor, the condition of the apartment and the building should decide, not the figure in the panel.
Comparing a net yield with gross yields. Many figures in the press or in listings are gross, i.e. before costs. Compare net with net.
Forgetting entry costs and financing. Furnishing, notary fees and interest can cut the return on your money by several percentage points.
Skipping the legal checks. A good yield is no help if the building is in seismic risk class I or the owners' association refuses its approval.
Using the PDF report as a valuation for the bank. It is an investment analysis, not an ANEVAR valuation report.

Frequently asked questions

How much does the KeyBid ROI Calculator extension cost?

Installation and the panel estimate cost nothing. You only pay if you generate a PDF report: 49.99 lei for listings in Romania and €24.99 for listings in Greece and Spain, once per report, with no subscription and no account.

Does it work on a phone?

No. The extension is available for Chrome and Firefox on desktop. On your phone, you can save the listings you are interested in and analyse them later on your laptop.

Why doesn't the panel appear on a listing?

Most often because the listing is not eligible: it is for rent rather than for sale, or it is a house, a villa, a plot of land or commercial premises. The panel does not appear in search results either, only on the listing page itself, and it needs a few seconds after the page loads. If the listing is an apartment for sale on Storia, Imobiliare.ro or OLX and the panel still does not appear, reload the page.

Can I use the PDF report for a mortgage?

You can use it in discussions with the bank to show how you calculated revenue, costs and yield. It is not a valuation report, though: for a mortgage, the bank requires a valuation by an ANEVAR-authorised valuer. The financing steps are in our guide to financing and due diligence.