A mortgage is probably the biggest debt you will take on, and it will last decades. These are the most frequent mistakes and how to avoid them.
1. Looking only at the TIN
The nominal interest rate does not tell the whole story. The TAE (the Spanish APR) includes compulsory fees and costs, so it is the figure that lets you compare best. Also look at which products you are asked to take out in order to get the advertised rate.
2. Not comparing offers
Each bank offers different conditions. Ask several banks for the European Standardised Information Sheet (FEIN) and compare the total cost, not just the payment. By law, at least 10 calendar days must pass between receiving the FEIN and signing, a period that cannot be shortened and that you can use to compare calmly.
3. Accepting the tie-in without calculating it
Discounting the rate in exchange for insurance, payroll or cards may or may not pay off. Add up what you will pay each year for those products and compare it with what you save in interest.
4. Borrowing to the limit
A payment that eats a large part of your income leaves you no margin. As a common reference, try to keep your debt payments at no more than around one third of your net income, and check what would happen if the rate rose: in our guide to fixed, variable and mixed mortgages you can see the payment at different rates.
5. Stretching the term without looking at the total cost
A longer term lowers the payment but greatly increases the interest. With 150,000 euros at 3%:
| Term | Monthly payment | Total interest |
|---|---|---|
| 15 years | €1,035.87 | €36,457 |
| 20 years | €831.90 | €49,655 |
| 25 years | €711.32 | €63,395 |
| 30 years | €632.41 | €77,666 |
Going from 20 to 30 years lowers the payment by about 200 euros, but costs more than 28,000 euros extra in interest. Simulate your case with the mortgage calculator.
6. Not using the pre-signing visit to the notary
Before signing you have the right to a consultation with the notary, which must take place at least one working day before the signing. There the notary explains the clauses and checks that you understand what you are signing. Make the most of it and bring your questions in writing.
7. Forgetting costs and fees
You have to count on the deposit, on the costs that fall to you, such as the valuation, and on the taxes and notary fees of the purchase. In the guide to mortgage costs you have the full split. Also check in the FEIN the fees for repaying early: the law limits them, but it is worth knowing how much it would cost to pay off sooner.
Quick summary
- Compare the TAE and the total cost, not just the payment.
- Ask for several FEIN documents and use the days before signing.
- Work out the real cost of the tie-in.
- Leave room in your budget in case rates rise.
- Use the pre-signing visit to the notary.
Frequently asked questions
How early should I start comparing offers?
As early as you can. Once you have a FEIN in hand you must have at least 10 calendar days before signing, so build in time for that.
Is it better to choose the lowest payment?
Not always. The lowest payment usually comes with a longer term and more interest in total.
Sources
- Tinsa: time between the FEIN and signing the mortgage (in Spanish)
- Banco de España: mortgage costs (in Spanish)
This article is for information and education only. It is not personalised financial, tax or legal advice: for an important decision, consult a qualified professional. Last reviewed: October 2026.