When we start looking for a property and need financing, one of the most important questions in the entire process inevitably comes up: which is better, a fixed or variable-rate mortgage? There is no single answer that works for every buyer. The right choice will depend on our financial circumstances, how long we intend to keep the mortgage, our tolerance for potential changes in monthly repayments and, of course, the specific terms offered by each lender. A fixed-rate mortgage allows us to know from the outset the interest rate we will pay throughout the life of the loan. By contrast, a variable-rate mortgage is usually linked to a reference rate, typically the Euribor, meaning that its cost can change over time. The Bank of Spain identifies this distinction as one of the key factors to consider before taking out a mortgage. Therefore, deciding which is better, a fixed or variable-rate mortgage, is not simply a matter of comparing which monthly repayment is lower today. We need to consider what could happen over the coming years and which financing structure best suits our circumstances. Fixed or variable-rate mortgage: what’s the difference ? The main difference lies in how the interest we pay is calculated. With a fixed-rate mortgage, the agreed interest rate remains unchanged throughout the loan term. This means that, provided we keep the same contractual terms, general changes in interest rates will not affect our monthly repayment. This provides predictability. From the outset, we can know how much we will pay towards our mortgage and plan our long-term budget more easily. With a variable-rate mortgage, the interest rate generally consists of a reference rate plus a margin set by the lender. In Spain, the 12-month Euribor is the most commonly used reference rate for this type of loan. For example, we might come across a mortgage charging the Euribor plus an agreed margin. When the loan is reviewed, usually every six or twelve months depending on the contract, the monthly repayment will be recalculated using the relevant value of the reference rate. If the Euribor rises, our repayment may increase. If it falls, we may benefit from a reduction. How does a fixed-rate mortgage work? A fixed-rate mortgage is primarily designed to provide stability. Imagine buying a property with a mortgage over 20 or 25 years at an agreed fixed interest rate. We will know from the outset what our monthly repayment will be, provided we do not subsequently make any changes to the loan. This predictability can be particularly valuable when we want to know precisely how much our home will cost us each month. It also protects us against future interest rate rises. If market rates increase, our mortgage will continue to be subject to the terms we originally agreed. The trade-off is that we will not automatically benefit from potential interest rate cuts either. If new mortgages begin to offer more favourable terms, our loan will retain its agreed interest rate unless we subsequently negotiate a change, arrange a mortgage novation or switch to another lender. For this reason, when considering which is better, a fixed or variable-rate mortgage, we should ask ourselves how much we value the certainty of a stable monthly repayment compared with the possibility of benefiting from future market movements. How does a variable-rate mortgage work? With a variable-rate mortgage, we accept that the cost of borrowing may change over time. The Bank of Spain explains that this type of financing is generally calculated by adding a reference rate to a fixed margin. Suppose, for example, that our mortgage agreement sets the interest rate at the Euribor plus a margin. Whenever a review is due, the lender recalculates the applicable interest rate based on the reference rate specified in the contract. This means that our monthly repayment does not necessarily remain the same throughout the life of the mortgage. For this reason, when considering a variable-rate mortgage, we need to look beyond the initial repayment and assess whether we could afford higher monthly payments if interest rates increased. There is specific documentation for variable-rate mortgages that uses simulations to illustrate how repayments could change under different interest rate scenarios. The Bank of Spain warns that these simulations are indicative only and should not be interpreted as predictions of future market movements. Advantages of a fixed-rate mortgage The main advantage is financial peace of mind. Knowing what our monthly repayment will be makes it easier to plan our household budget and removes the risk of an increase in the Euribor pushing up our mortgage payments. This can be particularly important when borrowing a substantial amount. Even a relatively small change in the interest rate can make a considerable difference when the outstanding loan amounts to several hundred thousand euros. For high-end property purchases, such as many of those found on the Costa del Sol, this is an especially important consideration. Taking on a change in repayments on a small mortgage is not the same as facing it on a substantial outstanding balance. A fixed-rate mortgage also makes long-term planning easier. We can factor our repayments into our regular expenses, knowing that market fluctuations will not directly change the amount we pay each month. However, this stability needs to be assessed alongside the price the lender charges for it. Advantages of a variable-rate mortgage A variable-rate mortgage has one feature that can make it attractive: the opportunity to benefit from falls in the reference rate. If the Euribor falls and our mortgage reaches its next review date, the applicable interest rate may decrease, reducing our monthly repayment. In addition, the initial terms offered on a variable-rate mortgage may differ from those available on a fixed-rate deal. We should therefore compare the actual offers available before ruling out either option. However, this potential advantage comes with uncertainty. The Euribor is influenced by multiple economic and monetary factors, and we cannot know with certainty where it will stand in five, ten or twenty years. The