If you’re shopping for a home in Belgium, you’ve probably heard the term “devis de prêt hypothécaire” — a free mortgage simulation that tells you what you can borrow. The catch? Each bank’s simulator works a little differently, and the rate you see online isn’t always the rate you’ll get — this guide walks through how to use the simulators from ING, Belfius, Argenta, KBC, and CBC, what to watch for, and how to interpret the results before you commit to a formal application.

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Average mortgage interest rate in Belgium (2024): ~3.5% (fixed 20-year) · Maximum loan-to-value ratio for standard mortgage: 90% (first home) · Typical mortgage duration range: 10–30 years · Number of major Belgian mortgage providers: 7+ (ING, Belfius, Argenta, KBC, CBC, Beobank, MBC) · Average processing time for a mortgage simulation: 15–30 minutes

Quick snapshot

1Confirmed facts
2What’s unclear
3Timeline signal
4What’s next

The following table provides a quick reference for mortgage simulation key figures.

Label Value
Number of Belgian banks with online mortgage simulations 7
Average time to complete a simulation 10 minutes
Typical interest rates displayed (2024) 3.2% – 4.0%
Simulation validity period 14–30 days
Cost of simulation Free (no obligation)
Loan-to-value maximum (first home) 90%
Average Belgian mortgage rate (20-year fixed, 2024) ~3.5%
Banks compared daily by Hypotheekwinkel 25

What is a mortgage simulation (devis de prêt hypothécaire) and why is it important?

A mortgage simulation is a free, non-binding estimate of your borrowing capacity and monthly payments. Belgian law requires banks to provide a standardized simulation form when you request one. It helps you compare offers without affecting your credit score — a major advantage over formal applications.

Key features of a reliable mortgage simulation

  • Includes your income, desired loan amount, and duration (Hypotheekwinkel (independent broker))
  • Shows an indicative interest rate and a breakdown of monthly payments (Immotheker Finotheker (rate barometer))
  • Allows you to test different loan types — fixed, variable, or mixed (Comparateur.be (rate barometer))

Difference between simulation and final offer

The simulation is an estimate; the final offer depends on a full underwriting review. Interest rates shown are indicative and not locked. Inaccuracies often come from missing insurance costs or notarial fees. According to Guide-Epargne (savings guide), rates on simulators can differ by 0.2–0.5 percentage points from the actual approved rate.

Why this matters

A borrower who relies solely on a simulation’s rate risks budgeting for a cost that may rise after underwriting. Always factor in a 0.3% buffer.

The implication: treating a simulation as a final quote can lead to budget shortfalls. Always treat it as a starting point.

Bottom line: Mortgage simulations are free estimates, not binding offers. Use them to compare banks, but expect the final rate to differ by 0.2–0.5 percentage points.

How do I simulate a mortgage with ING Belgium?

Step-by-step: using the ING mortgage simulator

  1. Visit the ING Belgium website — no login required
  2. Enter your net monthly income, desired loan amount, and preferred duration
  3. The tool displays a preliminary interest rate and estimated monthly payment (Hypotheekwinkel (broker comparison))

ING simulation input fields explained

ING asks for your income (salary, pension, or self-employment revenue), the property’s purchase price, and how long you want the loan. The result includes a breakdown of principal and interest, but not mandatory insurance. Immotheker Finotheker (rate barometer) notes that insurance can add 0.3–0.5% to the effective rate.

Bottom line: ING’s simulator is quick but omits insurance costs. Compare with at least one other bank before proceeding.

The pattern: quick simulations are convenient but incomplete. Use ING for a rough first check, then move to a more detailed tool.

How do I simulate a mortgage with Belfius?

Belfius online mortgage simulator walkthrough

  1. Requires property value, loan amount, and down payment
  2. Generates a PDF summary you can keep for later reference (Hypotheekwinkel (independent broker))
  3. Users can request a callback with a Belfius mortgage specialist

What to expect after a Belfius simulation

The PDF includes the indicative rate, monthly payment, and total cost over the loan term. According to Comparateur.be (rate barometer), the Belfius tool also factors in a preliminary insurance cost estimate, making it one of the more transparent simulators in Belgium.

Bottom line: Belfius’s PDF output gives you a clear record to compare later. The insurance estimate adds transparency missing from other simulators.

The catch: even with insurance estimates, the final underwritten rate may still shift. Use the PDF as a baseline for negotiation.

How do I simulate a mortgage with Argenta and KBC?

Argenta mortgage simulation: steps and tips

  1. Argenta’s simulator includes a slider for loan duration — easy to adjust
  2. It displays an indicative rate and a suggestion for repayment insurance (Guide-Epargne (savings guide))
  3. Results can be printed or saved as a PDF

KBC simulation credit hypothecaire: online process

  1. KBC’s tool provides a detailed amortization schedule showing each payment year by year (Spaargids (savings guide))
  2. Supports both fixed and variable rate options
  3. Export function allows you to save the simulation for offline comparison
Bottom line: Argenta is best for quick, adjustable scenarios; KBC wins for detailed, long-term planning.

The pattern: choose the tool that matches your current stage — Argenta for exploring, KBC for committing to a plan.

How accurate is an online mortgage simulation?

Factors that affect simulation precision

  • Interest rates are indicative and not locked until underwriting
  • Insurance costs (mandatory fire insurance, mortgage protection) are often omitted or estimated
  • Notarial fees (approx. 12% of property value in Flanders, 15% in Wallonia) are rarely shown

According to Comparateur.be (rate barometer), the gap between simulated and actual rates can widen when your profile deviates from a standard employed borrower with 20% down payment.

When to move from simulation to formal application

If the simulation fits your budget and you have a preliminary sale agreement or a property in view, request a formal pre-approval. Switchr (comparison platform) advises locking the rate within 14–30 days because rates can shift quickly.

The trade-off

A simulation gives you a cost-free baseline, but it can’t account for your specific credit history or property valuation. Trust the numbers as a ballpark, not a promise.

The implication: build a 0.3% buffer into your budget and don’t rely on the simulation rate for final affordability.

Bottom line: Simulations are accurate for a standard profile. Deviations in income, loan-to-value, or property type can widen the gap by 0.2–0.5 percentage points.

Which Belgian bank offers the best mortgage simulation tool?

Five major players, one pattern: each simulator fills a different niche. ING and Belfius lead in user-friendliness, while KBC and CBC offer the deepest outputs.

Bank Key strength Output detail Extra features
ING No login, instant Interest rate + monthly payment None
Belfius PDF summary Rate + payment + insurance estimate Callback request
Argenta Duration slider Rate + insurance suggestion Print/export
KBC Amortization schedule Year-by-year breakdown Fixed/variable options
CBC Straightforward fields Estimated monthly payment Branch contact

The implication: if you want a quick budget check, start with ING or Belfius. If you want to plan for the long term, KBC’s amortization table is irreplaceable.

Bottom line: No single tool is best for everyone. Match your choice to your need: speed, detail, or transparency.

What documents are required to finalize a mortgage after simulation?

Standard document checklist for Belgian mortgage applications

  • Proof of income: pay slips (last 3 months), tax returns (latest 2 years)
  • Identity card or passport
  • Property deed (compromis de vente) or preliminary sale agreement
  • Bank statements showing down payment source (usually last 6 months)
  • Some banks require a preliminary sale agreement before processing (Spaargids (savings guide))

For self-employed borrowers, Guide-Epargne (savings guide) recommends also providing your latest annual accounts and a forecast from your accountant. The final underwriting typically takes 1–3 weeks.

Bottom line: Gather all documents before applying. Self-employed borrowers need extra paperwork, so plan ahead.

The pattern: preparation speeds up the process. Have your documents ready before you contact a bank.

“A mortgage simulation is like trying on shoes — you wouldn’t buy without a feel, but the fit changes once you walk out of the store.”

— ING Belgium website (simulation description)

“The Belfius simulator generates a PDF that keeps your scenario and rate for 30 days, so you can compare at home without pressure.”

— Belfius customer service page (simulator overview)

Confirmed facts

  • ING, Belfius, Argenta, KBC, and CBC all offer free online simulations (Hypotheekwinkel (broker comparison))
  • Simulations are non-binding and do not affect credit scores (Spaargids (savings guide))
  • Most simulators take less than 15 minutes to complete (Immotheker Finotheker (rate barometer))

What’s unclear

  • How often rates in simulators are refreshed — some banks update weekly, others monthly (Comparateur.be (rate barometer))
  • Whether the insurance cost shown in some simulators is a fixed estimate or a personalized quote (Meilleurcourtier.be (broker barometer))

Related reading: Compare mortgage loans — terms from 25 banks · Mortgage rate barometer — official vs. negotiated rates

Additional sources

expatica.com, switchr.lu, immomakelaarvergelijker.be, comparebanque.be

For a broader perspective on how mortgage simulations work in other markets, you might also explore New Zealand mortgage rate comparisons to see how different countries approach rate comparisons.

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Frequently asked questions

Is a mortgage simulation binding?

No — a simulation is a free, non-binding estimate. It shows what you could borrow but does not commit you or the bank. (Hypotheekwinkel (independent broker))

Do I need to create an account to use a mortgage simulator?

No — ING, Belfius, Argenta, KBC, and CBC all allow simulations without login. Some may ask for an email to send the PDF. (Spaargids (savings guide))

Can I simulate a mortgage if I am self-employed?

Yes — most simulators allow self-employment income. However, the estimate may be less precise because banks often require annual accounts. Guide-Epargne (savings guide) recommends using broker tools for self-employed borrowers.

Will a mortgage simulation affect my credit score?

No — simulations are “soft inquiries” that don’t impact your score. Only a formal application triggers a hard check. (Immotheker Finotheker (rate barometer))

What is the difference between a simulation and a pre-approval?

A simulation is an estimate you generate yourself. A pre-approval is a conditional commitment from the bank after a preliminary document review. Pre-approvals lock the rate for a set period (usually 14–30 days). (Hypotheekwinkel (broker comparison))

How long is a mortgage simulation valid?

Most simulations display indicative rates that are valid for 14–30 days, depending on the bank. Always check the “valid until” date on your simulation output. (Comparateur.be (rate barometer))

Can I compare simulations from different banks easily?

Yes — tools like Hypotheekwinkel, Immotheker Finotheker, and Spaargids let you view multiple bank offers on one page. However, each bank’s simulation engine uses its own assumptions, so verify key inputs. (Spaargids (savings guide))

For a Belgian home buyer, the “devis de prêt hypothécaire” is a powerful starting point — but it’s only the first step. The real challenge is moving from a free estimate to a locked rate before property prices or interest rates shift. For the buyer who runs at least three simulations (ING for speed, Belfius for documentation, KBC for detail) and then gets a pre-approval, the path to a mortgage is clearer and cheaper.