Buying Abroad: How to Adapt the Simulator to Your Country

Buying abroad: why your usual buy or rent math breaks down

When you buy property abroad, the usual French acheter ou louer logic no longer applies as‑is. Mortgage rates, local inflation, closing costs (the foreign equivalent of French notary fees, i.e. the montant_fn parameter) can be radically different from what you know in France.

If you plug French defaults into an international buy or rent decision, your result will be misleading. The goal here is not to tell you to buy or to rent abroad — that always depends on your personal and tax situation — but to show how to correctly tune three critical simulator parameters for an international context:

• inflation_annuelle: the inflation rate of the country where the property is located
• taux_pret: the local mortgage rate, often far from the ~3.6% currently seen in France
• montant_fn: all purchase / closing costs in the target country (notary, lawyer, taxes, registration)

All numbers below are indicative and change over time. They are not personalized financial advice. To really compare buy or rent, you must test your own assumptions. Simulate your situation on buy-or-rent.net.

1. Annual inflation: the hidden driver of international buy or rent decisions

1.1. What inflation_annuelle does inside the simulator

In a buy or rent simulator, the inflation_annuelle parameter is used to:

• index future rents if you stay a tenant (in France, that’s the IRL index)
• revalue expenses and sometimes the real value of your property over time

For an international project, you must use the local inflation of the country where the property is, not the French inflation rate, even if you remain a French tax resident.

Typical averages in recent years (rough orders of magnitude):

• Euro area core countries: 2–4%
• USA: 3–6% depending on the year
• UK: 3–8% over 2021–2023
• Some emerging markets: 10–20% or more

Between a 2% inflation country and a 10%+ inflation country, rent dynamics, property prices and your real purchasing power evolve very differently. Your international acheter ou louer comparison must capture that.

1.2. Numerical example: same flat, two inflation regimes

Imagine you compare buying or renting an equivalent apartment abroad:

• Purchase price: €200,000
• Starting rent: €900 / month
• Time horizon: 15 years

Case A – low inflation country (inflation_annuelle = 2%)

• Average rent increase: 2% / year
• After 15 years, rent ≈ 900 × (1.02)¹⁵ ≈ €1,213 / month
• Total rent over 15 years ≈ €207,000 (roughly)

Case B – high inflation country (inflation_annuelle = 8%)

• Average rent increase: 8% / year
• After 15 years, rent ≈ 900 × (1.08)¹⁵ ≈ €2,853 / month
• Total rent over 15 years ≈ €365,000 (order of magnitude)

With 8% inflation, renting becomes much more expensive over time. But property‑related costs (tax, maintenance, insurance) also rise faster. This is why correctly setting inflation_annuelle is crucial when you buy abroad and run an international simulation.

1.3. How to choose a realistic inflation_annuelle for a foreign country

To set inflation_annuelle in your international buy or rent simulation:

• Look up the country’s inflation average over 5–10 years (central bank, IMF, national statistics)
• Avoid relying on a single exceptional year (energy shock, currency crisis)
• For volatile countries, run several scenarios: for example 5%, 10%, 15%

Examples:

• Stable economies (euro area core, Canada, Switzerland): you might test 2–3%
• More unstable or emerging markets: you may want to run 3 scenarios at 5%, 10% and 15%

The goal is not to guess the exact future inflation, but to see how sensitive your acheter ou louer result is to local inflation.

2. Mortgage rate (taux_pret): big cross‑country gaps

2.1. France vs the rest: today’s mortgage landscape

In France, standard mortgage rates are currently around 3.6% for 20 years, with borrower insurance (taux assurance) often adding 0.25–0.45%. Many French‑based buy or rent simulations use something close to this.

Abroad, the picture is very different:

• Germany / Netherlands: sometimes similar or slightly lower than France, depending on the period
• USA: typical 30‑year fixed mortgage rates in the 5–7% range in recent years
• Central / Eastern Europe or Latin America: mortgage rates can exceed 10–12%
• Markets dominated by variable rates: your effective cost depends heavily on future rate hikes

If you keep 3.6% as taux_pret in a country where real rates are 7–9%, your international buy or rent result will be heavily biased in favor of buying.

2.2. Example: same price, different taux_pret

Take a €200,000 property abroad, financed 100% over 20 years (we ignore borrower insurance for clarity here).

• Country A: taux_pret = 3.6%
• Country B: taux_pret = 7%

Country A – 3.6% over 20 years

• Monthly payment ≈ €1,170 (principal + interest)
• Total interest over 20 years ≈ €80,800

Country B – 7% over 20 years

• Monthly payment ≈ €1,550
• Total interest over 20 years ≈ €172,000

In the 7% country, you pay more than twice as much interest. In a buy or rent comparison, this can tilt the balance towards renting, especially if local rents are low relative to property prices.

2.3. Fixed vs variable: how to reflect risk in your simulation

Many countries rely heavily on variable or indexed mortgages. For a serious international simulation, you should:

• Run a baseline scenario with the current taux_pret (e.g. 6%) staying stable
• Run a stress scenario with +1 or +2 percentage points (e.g. 7–8%)

Example for a €200,000 loan over 20 years:

• At 6%: monthly ≈ €1,433, total interest ≈ €143,900
• At 8%: monthly ≈ €1,673, total interest ≈ €201,500

That €57,600 difference in interest can fund several years of rent in some markets. Your international acheter ou louer decision is therefore highly sensitive to taux_pret in high‑rate countries.

2.4. Choosing a realistic taux_pret when you buy abroad

To tune taux_pret in a foreign buy or rent simulation:

• Check average mortgage rates from local banks or comparison websites
• Identify if rates are fixed, variable, or fixed for an initial period then variable
• Add a prudence buffer (0.5–1 percentage point) in your stress scenario

Example: a bank abroad offers a 5.5% variable mortgage indexed to a policy rate.

• Central scenario: taux_pret = 5.5%
• Prudent scenario: taux_pret = 6.5%

Run both in your buy or rent simulator to see how sensitive your outcome is to higher rates.

3. montant_fn: local purchase / closing costs matter more abroad

3.1. What “montant_fn” covers in an international context

In France, montant_fn approximates notary fees (7–8% for existing property, 2–3% for new build). Abroad, the cost structure is different but you can still aggregate it into this single parameter:

• Lawyer or notary fees
• Transfer taxes / stamp duty / registration taxes
• Land registry, mortgage registration
• Buyer‑side agency fee (in some markets the buyer pays part of the commission)

In an international buy or rent simulation, you set montant_fn as a percentage of the purchase price, based on all these items.

3.2. Example purchase costs in different markets

Typical ranges (strongly country and region‑dependent):

• France: 7–8% existing, 2–3% new build (excluding agent fee when paid by buyer)
• Spain: roughly 10–13% (regional transfer tax, notary, registry, sometimes lawyer)
• Portugal: 7–10%
• UK: 5–10% depending on price (Stamp Duty + legal fees + survey, etc.)
• USA: often 2–5% for the buyer, but beware of high annual property tax

On a €250,000 property, going from 4% to 12% in montant_fn changes your upfront cash need by €20,000.

3.3. Numerical example: impact of montant_fn when you buy abroad

Compare buying vs renting the same type of property in two countries, price €250,000:

• Country A: montant_fn = 4%
• Country B: montant_fn = 12%

Country A – 4% closing costs

• Upfront purchase costs = 250,000 × 4% = €10,000
• Total initial outlay ≈ €260,000 (excluding renovation)

Country B – 12% closing costs

• Upfront purchase costs = 250,000 × 12% = €30,000
• Total initial outlay ≈ €280,000

The extra €20,000 could either:

• increase your mortgage size (and hence interest costs)
• or tie up more of your cash that you could otherwise invest if you stayed a renter

In a country where you expect to sell again after only 5 years (expat contract, political risk, work mobility), high entry costs make buying less attractive. A good buy or rent simulator will show that once you feed in the right montant_fn.

3.4. Don’t forget recurring local costs

montant_fn is only the entry ticket. When you buy abroad you also need to consider:

• Property tax (often much higher than in France in places like the US or Canada)
• Management fees if you let the property while living elsewhere
• Renovation / compliance work (energy performance, seismic codes, condo rules), which goes into the simulator’s renovation cost parameter

These are not part of montant_fn but they heavily influence your international acheter ou louer outcome.

4. Building a robust international buy or rent comparison

4.1. Start with three country‑specific parameters

To make your international simulation meaningful, always adapt at least these three to each country:

• inflation_annuelle: average local inflation
• taux_pret: realistic local mortgage rate (plus a stress scenario)
• montant_fn: all purchase / closing costs rolled into a percentage

Then refine with:

• local investment rate (what you can earn on ETFs or savings if you rent)
• expected property tax increase if reassessments are frequent
• potential prepayment penalties if you might sell early

4.2. Worked example: buy abroad vs rent at home

Assume you can either:

• buy a flat in Country X (moderate inflation, low rates, moderate fees)
• stay a renter in Country Y (where you currently live) and invest your savings

Country X (buy scenario)

• Purchase price: €220,000
• taux_pret: 3.5% over 20 years
• montant_fn: 5% → €11,000
• inflation_annuelle: 2.5%
• Property tax: €800 / year, rising 2% annually

Country Y (rent + invest scenario)

• Starting rent: €950 / month
• inflation_annuelle on rent: 4%
• Net investment return (after local inflation): 4.5% / year

In the simulator you would:

• Scenario A: model buying in X with local inflation, taux_pret and montant_fn
• Scenario B: model renting in Y, investing the initial €11,000 + any monthly saving vs the mortgage into a portfolio earning 4.5% net

Over 10, 15, 20 years, you compare your net worth in both cases: value of the property in X (minus remaining debt and selling costs) vs financial portfolio in Y. This is the essence of an international acheter ou louer analysis.

5. What the simulator won’t capture (and you must still think about)

Even a well‑tuned buy or rent model with correct inflation_annuelle, taux_pret and montant_fn cannot fully capture:

• Currency risk if your income is in euros but your mortgage is in another currency
• Political / regulatory risk (new taxes on foreign owners, rent controls, restrictions on tourist rentals)
• Rental risk (void periods, non‑paying tenants, changing local rules)
• Cross‑border tax issues (double taxation, social charges, treaty nuances)

These elements can materially change whether buying abroad is better than renting and investing. A simulator is an aid, not a substitute for professional advice.

This content is general and informational. It is not personalized financial, legal or tax advice. Before acting on an international buy or rent decision, speak with qualified professionals in the relevant countries.

Conclusion: international buy or rent is all about parameters

There is no universal answer to the question “should I buy abroad or keep renting?”. Your optimal choice depends on:

• how long you will stay or hold the property
• local inflation_annuelle and economic stability
• the level and structure of taux_pret
• the weight of montant_fn and other country‑specific costs

By carefully adapting these three parameters to each country you consider, an international buy or rent simulator becomes a powerful tool to compare, in hard numbers, buying abroad versus renting and investing your capital.

To explore different countries, stress‑test assumptions and see how inflation, mortgage rates and closing costs shape your decision, use a dedicated simulator. Simulate your situation on buy-or-rent.net and, for the French version, Simulez votre situation sur acheter-ou-louer.com.