Mortgage Calculator
Calculate the monthly payment, total cost and full breakdown of principal and interest of your loan.
This calculator uses the French amortisation system (constant payment), the most common in Spanish mortgages. The monthly payment is fixed throughout the term.
Capital vs interest
Breakdown of total loan cost
Amortisation table (first 10 years)
| Year | Annual payment | Interest | Principal repaid | Outstanding balance |
|---|---|---|---|---|
| Enter the data to see the table | ||||
How does the French amortisation system work?
In the French system, the monthly payment is always the same. However, the proportion of interest and principal changes over time: at first you pay more interest and less principal; as the loan progresses, you pay more principal and less interest.
Mortgage loan elements
- TIN (Nominal Interest Rate): the rate that determines the loan's interest. Does not include other loan costs.
- TAE (Annual Equivalent Rate): includes TIN plus commissions and other costs. It is the most representative indicator of the real cost. This calculator uses TIN, so the real cost may be somewhat higher.
- Term: a longer term means lower monthly payment but higher total interest cost. It is generally advisable to reduce the term where possible.
Fixed or variable mortgage?
A fixed-rate mortgage keeps the interest rate constant throughout the life of the loan, offering security. A variable-rate mortgage is reviewed periodically according to Euribor or another index, which may mean lower or higher payments depending on how the index evolves.
This calculator simulates a fixed-rate mortgage. For variable rates, the monthly payment would change with each review.
How the monthly payment is calculated
In the French system, the payment is calculated so the loan is fully repaid by the end of the term with equal installments. The formula is:
- Principal = loan amount
- i = monthly interest rate (annual nominal rate ÷ 12)
- n = number of payments (years × 12)
Each payment includes part interest (on the outstanding principal) and part principal repayment. At the start interest dominates; toward the end, repayment does.
Example: a €150,000 mortgage over 25 years at 3%
With a €150,000 loan over 25 years (300 payments) at a 3% nominal rate, the monthly payment is around €711. Over the life of the loan you would pay about €213,000, of which nearly €63,000 is interest. If the same loan were over 20 years, the payment would rise to about €832 but total interest would drop to ~€50,000: you pay more each month, but the loan costs you considerably less overall.
Common mistakes when taking out a mortgage
- Looking only at the monthly payment. A low payment with a very long term can mean tens of thousands more in interest. Look at the total cost too.
- Ignoring the APR and associated costs. Arrangement fees, appraisal, linked insurance… The APR reflects the real cost better than the nominal rate.
- Extending the term too far. Each extra year lowers the payment but makes the loan more expensive. Choose the shortest term your budget can comfortably handle.
- Forgetting early repayment. Repaying principal in the early years, when interest dominates, is when you save the most. Check the early-repayment fees.
Frequently asked questions about mortgages
What is the difference between the nominal rate and the APR?
The nominal rate is the interest applied to the principal. The APR also includes fees and other loan costs, so it better reflects the real cost. This calculator uses the nominal rate, so your mortgage's effective cost may be somewhat higher.
Is a shorter or longer term better for me?
A shorter term means a higher monthly payment but far less total interest. A longer term eases the payment but makes the loan more expensive. The usual advice is to choose the shortest term you can take on without straining your monthly budget.
Is early repayment worth it?
Generally yes, especially in the early years when most of the payment is interest. You can choose to reduce the payment (pay less each month) or reduce the term (finish sooner and save more interest). Check whether your mortgage has an early-repayment fee.
Fixed or variable mortgage?
A fixed mortgage keeps the same payment for the whole loan and offers security against rate rises. A variable one is reviewed against the Euribor and can end up cheaper or more expensive. The choice depends on your risk tolerance and current conditions.
How much can I borrow based on my income?
A prudent rule is that the payment should not exceed 30-35% of your net monthly income, including all your debts. Lenders usually finance up to 80% of the appraised value, so you will need savings for the down payment and costs.
