Fixed, Variable and Mixed Rates

Reviewed · 5 October 2026

A desk with three different loan scenario sheets showing only abstract unlabelled line graphs.

Your starting point

Compare what you would pay across different assumptions. A calculator helps you explore a scenario; only a lender can assess an application and offer credit.

Fixed, variable and mixed rates distribute interest-rate uncertainty differently over the loan period. Use the steps below to organise a decision, not to infer an official approval, a guaranteed price or a universal deadline.

Work through the decision

Fixed, Variable and Mixed Rates — a diagram of the key planning steps — Planning diagram. The same steps are described in the text below.

Identify the structure

A fixed period holds the rate; variable periods can change under the contractual formula.

Check the transition

For a mixed rate, record when the fixed period ends and how the later rate is determined.

Compare scenarios

Model alternative rates and ask for the lender's standardised information and full charges.

Adapt this to your circumstances

Keep citizenship, current residence, household needs and the location of the home separate in your notes. Ask the responsible authority, institution or qualified professional to confirm any requirement that affects your situation. A checklist used by another household may not apply to yours.

Sources and checks

Banco de Portugal — mortgage interest rates — an official starting point for this topic. The relevant page, its scope and effective date must be checked before a consequential decision.

No market prices, eligibility thresholds or legal deadlines have been invented for this guide. Dates in personal planning tools are suggestions or values you supply.