Card Parameters
📊 Amortization Breakdown
The use of revolving credit cards is one of the most controversial borrowing options in Spain. Unlike traditional credit cards, where the balance spent is paid in full at the end of the billing cycle without interest, revolving cards allow you to defer repayments through low, fixed monthly payments. However, this flexibility comes at a very high cost, as interest rates are typically double those of standard personal loans, and monthly compounding can turn a small balance into a lifelong financial burden.
Our calculator simulates the month-by-month amortization of your debt in 2026 using the nominal interest rates (TIN) applied. In addition to projecting the total time required to pay off your balance and the total interest generated, it features a built-in safety check that automatically alerts you if your chosen monthly payment is insufficient to cover the monthly interest accrued, a common trap in revolving card agreements.
⚙️ The Mathematical Trap of Revolving Credit
The danger of revolving credit lies in how payments are distributed each month:
- Interest priority: From your monthly payment, the bank first deducts the interest generated during that month (calculated as Current Balance multiplied by TIN / 12).
- Residual principal repayment: Only the remaining portion of your monthly payment is used to reduce the actual outstanding principal.
- Infinite debt loop: If your monthly payment is set too low, it may only cover the monthly interest. As a result, the principal balance never decreases, and the debt persists indefinitely.
📊 Practical Examples of Revolving Card Amortization
These two examples show how monthly payment amounts affect your overall interest costs:
- Outstanding balance: **€3,000.00**
- Nominal interest rate (TIN): **20.00%** (1.67% monthly rate)
- Monthly payment: **€150.00**
- First month interest: €3,000.00 multiplied by 1.67% = **€50.00** (reducing principal by €100.00)
- Outstanding balance: **€3,000.00**
- Nominal interest rate (TIN): **20.00%**
- Monthly payment: **€60.00**
- First month interest: **€50.00** (reducing principal by only €10.00)
⚠️ Common Credit Card Pitfalls
1. Setting the minimum allowed payment
Credit card companies often permit very low minimum payments, sometimes just 2.00% or 3.00% of the balance or a flat €15.00. Choosing this option ensures that almost your entire payment goes toward interest, dragging out the debt for years.
2. Ignoring usury limits set by the Supreme Court
In Spain, the Supreme Court rules revolving card contracts as null and void if the annual percentage rate (TAE) exceeds the average market rate published by the Bank of Spain for that period by more than 6 percentage points.
3. Continuing to use the card during repayment
If you continue to make purchases with the card while trying to pay down an existing balance, you increase the outstanding principal. This resets the interest calculations and extends the repayment timeline.
❓ Frequently Asked Questions (FAQ)
If your monthly statements show you pay back your balance through a fixed monthly fee or a percentage of the debt, rather than paying off the full amount spent at the end of the month, it is a revolving card. These cards also feature high annual rates, typically above 15.00% TIN.
If a court declares your contract void due to usury, the contract is canceled. The bank must refund all interest and fees you paid over the life of the card, and you only have to pay back the actual principal amount you spent.
According to monthly statistics from the Bank of Spain, the average interest rate for deferred credit card payments historically ranges between 16.00% and 18.00% TIN, with some annual rates exceeding 20.00% TAE.
Yes, legal claims to declare a loan contract null due to usury under the 1908 Usury Act do not expire. You can sue to recover excess interest even if the card was opened years ago or has already been closed.
The fastest way is to ask your bank to increase your monthly payment to the maximum possible to pay down the principal, or make a lump-sum payment. Another option is consolidating the debt with a personal loan at a lower interest rate.
Yes, withdrawing cash using a revolving card usually triggers a withdrawal fee which is added to your card balance, immediately accruing the high nominal interest rate of the card from the day of withdrawal.