The rise affects mortgages linked to the three-, six- and 12-month Euribor rates, according to calculations by DECO Proteste/Contas e Direitos for Lusa.

The simulations are based on a €150,000 mortgage over 30 years with a 1% spread.

For a mortgage linked to the 12-month Euribor and revised in September, the monthly payment will rise to €712.15. This represents an increase of €70.48 compared with the payment following the previous annual revision in September 2025.

Those with mortgages linked to the six-month Euribor will also see an increase. The monthly payment in the example rises by €47.42 to €691.53 compared with the previous revision in March.

For mortgages using the three-month Euribor, the increase is smaller but will still add €23.82 to the monthly bill. The payment rises to €674.66 compared with the previous revision in June.

The increases follow a rise in average Euribor rates during August.

The monthly average stood at 2.513% for the three-month Euribor, 2.713% for six months and 2.954% for 12 months.

For variable-rate mortgages, the Euribor average used when revising the loan is generally the average from the month before the month in which the contract is reviewed.

The six-month Euribor remains the most widely used of the three main rates for variable-rate home loans in Portugal.

According to June data from the Bank of Portugal, mortgages linked to the six-month Euribor account for 39.9% of the stock of variable-rate loans for permanent homes.

The 12-month rate accounts for 31.3%, while mortgages linked to the three-month Euribor represent 24.38%.

The figures mean that borrowers whose contracts come up for revision in September should expect higher payments, although the exact increase will depend on the outstanding loan amount, remaining term, spread and Euribor rate used in each individual contract.