The euribor complicates variable mortgages again. The main index used in Spain to update this type of loan ends August close to 3%, after several months of increases that have reversed the downward trend observed at the end of 2025 and the beginning of this year.
With the last working session of the month pending, the provisional average for August stands around 2.95%, compared to 2.855% in July and 2.114% recorded in August 2025. The last available daily figure, corresponding to Friday the 28th, was 2.956%.
The definitive figure for August will be published by the Bank of Spain on September 1 and will subsequently have official status once it appears in the BOE.
The euribor has already exceeded 3% on several days in August
Although the monthly average still remains slightly below 3%, the index has already surpassed that barrier in daily quotes.
On August 21, it reached 3.003% and on the 26th it hit 3.007%, levels not seen for more than two years. On August 28, it slightly retreated to 2.956%.
However, what is important for a mortgagor is not the value of a specific day. Entities usually use the monthly average of the euribor established by the contract to calculate the new interest rate at each review.
Therefore, the index exceeding 3% on a given day does not imply that the payment automatically rises to that level.
A mortgage of 150,000 euros can increase by more than 800 euros a year
The impact will depend on the outstanding capital, the differential signed with the bank, the years remaining to finish the loan, and whether the review is done every six or twelve months.
HelpMyCash calculates the effect for a variable mortgage of 150,000 euros over 25 years with a differential of 1% over the euribor.
If the review is annual and an euribor of around 2.95% is taken as a reference, the monthly payment would approximately rise from 720 to 788 euros.
This means: 68 euros more per month and around 816 additional euros over the next twelve months.
The reason is that the last annual review would have been conducted using an euribor from August 2025 set at 2.114%. The difference compared to the current figure is approximately 0.84 percentage points.
What happens if the mortgage is reviewed every six months
Mortgages subject to a semi-annual update will also become more expensive. In the same example of 150,000 euros, 25 years, and a differential of 1%, the payment would approximately change from 727 to 788 euros monthly. The increase would be around 59 euros per month, which translates to about 350 additional euros over the next six months.
In this case, the comparison is made with February, when the Euribor was at 2.221%. The difference is smaller than in an annual review, but enough to cause a significant increase in the monthly payment.
How much it can increase according to the outstanding amount
Not all mortgaged individuals will pay 68 euros more. That figure corresponds only to a specific example.
The greater the capital remaining to be repaid and the more years left on the mortgage, the greater the effect of an increase in the Euribor.
The differential also influences this. A mortgage contracted at Euribor +0.50% will have a lower final rate than another signed at Euribor +1.50%, even if both are reviewed on the same day.
Additionally, in the French amortization system commonly used in Spain, the composition of the payment changes over the years. Therefore, an increase in the index usually has less impact on a mortgage nearing completion than on one that has just begun.
It does not affect fixed-rate mortgages
The increase also does not directly affect all homeowners with a mortgage loan.
Those with a fixed-rate mortgage will continue to pay the same payment, regardless of whether the Euribor is at 2%, 3%, or exceeds those levels.
The impact primarily falls on variable-rate mortgages and on those mixed-rate mortgages that have completed their initial fixed-rate period and have already entered the variable phase.
In fact, a growing portion of new operations is signed at a fixed rate. The latest available data from the INE showed that 61% of the mortgages constituted in May used a fixed interest rate.
From just over 2.1% to 2.95% in a year
The year-on-year evolution explains why some families will again face significant increases.
The Euribor closed August 2025 at 2.114%. It then remained for months around 2.2%, until it began a more pronounced acceleration during the spring of 2026.
In March it was at 2.565%; April ended at 2.747%; May at 2.804%; June at 2.798% and July officially reached 2.855%, according to the Bank of Spain.
August will likely raise that reference to approximately 2.95%, the highest monthly level since 2024.
Why the euribor is rising again
The increase coincides with a scenario of higher expectations about interest rates in the eurozone.
The euribor reflects the cost at which major European banks lend money to each other and usually anticipates expectations about the upcoming decisions of the European Central Bank. The rise in inflationary pressures and doubts about the future evolution of rates have led the market to discount a more restrictive monetary environment than was expected a few months ago.
This explains why the index has risen from 2.221% in February to almost 3% in just six months.
The key to knowing if your payment will rise in September
It is not enough to check that the euribor has increased. The mortgagor must review their deed or mortgage contract to know when the loan is updated and what specific reference the bank uses.
There are loans that are reviewed once a year and others every six months. In addition, the clause may establish the euribor published in a specific month prior to the review date.
If the update scheduled for September ultimately uses the euribor from August 2026, the result will generally be an increase for variable mortgages: the reference is now around 2.95%, compared to 2.114% a year ago and 2.221% six months ago.
For a typical mortgage of 150,000 euros, the increase may exceed 800 euros over the next year. The exact amount, however, will always depend on the outstanding capital, the term, the differential, and the specific conditions signed with the bank.