How is interest on a court judgment calculated?

Question

José Manuel Alburquerque · Accepted Answer

From the moment the first-instance judgment ordering payment of a sum of money is given, that sum bears annual interest equal to the statutory interest rate plus two percentage points, unless the parties had agreed on a different rate or a law sets a special one. In 2026 the statutory interest rate is 3,25 %, so the rate on the judgment is 5,25 % a year. It is calculated day by day on the amount owed, from the date of the judgment until payment, at the rate for each year. Interest for the period before the judgment, on the other hand, generally has to be requested in the claim and depends on the type of debt. Interest on the judgment The law calls it post-judgment interest (“intereses de la mora procesal”) and its purpose is to ensure that delaying payment does not pay off for the party ordered to pay. It is owed even if nobody asks for it and applies to any order to pay a liquidated sum, that is, a sum fixed in euros. It also applies to arbitral awards and to mediation agreements requiring payment. It is governed by the “Ley de Enjuiciamiento Civil”, Spain's Civil Procedure Act, which is the same throughout Spain. The statutory interest rate is set each year by the State Budget Act (the “ley de presupuestos del Estado”). In 2026 it is still the 2023 rate, because that year's budget is still being rolled over. At 5,25 % a year, a judgment for 20.000 euros generates 1.050 euros of interest a year, about 2,88 euros a day. If the party ordered to pay settles 200 days after the judgment, within 2026, it owes about 575 euros in interest. If there is an appeal and the judgment is upheld, interest runs from the first-instance judgment. If it is partly overturned, for example because the “Audiencia Provincial” (the provincial appeal court) reduces the amount, the court decides, giving reasons, from when and on what amount interest is owed. If the order to pay is made for the first time on appeal, interest in principle runs from that judgment. Interest before the judgment Interest for delay before the judgment is generally not awarded automatically. It has to be requested in the claim and depends on the debt: In general, anyone who is late in paying a sum owes the agreed interest or, if nothing was agreed, interest at the statutory rate from when payment was demanded of them, in writing or by means of the claim. Between businesses and the self-employed, in their commercial transactions, the Spanish late payment act (“ley de lucha contra la morosidad”) sets a higher rate, the European Central Bank rate plus eight percentage points, which runs from when the time limit for payment expires without any need to demand it. Insurers that delay without justified cause pay a special, higher rate of interest, which the judgment imposes on them even if it has not been requested. When the amount was not known until the judge set it, as happens with many compensation awards, the courts decide case by case from when that interest is owed, depending on whether or not it was reasonable for the debtor to dispute the debt. When the judgment is enforced, the court calculates all the interest due and the party ordered to pay can dispute the calculation.