Euribor averages 3.247% in September, up from August

The 12-month Euribor averaged 3.247% in September 2026, rising from 2.954% in August and 2.172% a year earlier, according to European Central Bank data. The benchmark is used to set the interest rate on most variable-rate mortgages in Spain, which are commonly reviewed once or twice a year.

Illustrative mortgage impact

For a €150,000 mortgage over 25 years at Euribor plus 0.99%, a calculation using the September rate gives a monthly payment of about €811.52. On the same assumed balance and term, the September 2025 rate would produce a payment of €724.02, a difference of €87.50 a month, or about €1,050 over a year.

For a six-monthly review, the comparison with March 2026's 2.565% average gives an estimated payment increase of €56.15 a month, from €755.37 to €811.52. These are like-for-like examples that hold the balance and term constant. A borrower's actual balance usually falls over time, so their increase would be somewhat smaller, and the new rate applies only when the loan is reviewed using September's figure.

The monthly average ranged from 2.172% to 3.247% between September 2025 and September 2026.

Source: European Central Bank.