Legal Interest Calculator 2026
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Legal Interest Calculator
Calculate legal interest on an amount for a specific period, with rates updated to 2026.
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How the Legal Interest Calculator Works
The legal interest calculator is an essential tool for lawyers, accountants, and individuals who need to determine the interest owed under Article 1284 of the Italian Civil Code. Legal interest represents the compensation owed to a creditor for late payment of a sum of money, and its rate is set annually by decree of the Ministry of Economy.
What Is the Legal Interest Rate
The legal interest rate is the percentage established by law that applies when the parties have not agreed on a different rate. Article 1284 of the Civil Code provides that, in the absence of a different agreement, interest is calculated at the legal rate. Since 1 January 2026 the legal rate is 1.60% a year, set by the decree of the Ministry of Economy and Finance of 10 December 2025 (Official Gazette no. 289 of 13 December 2025); in 2025 it was 2%. This rate has undergone significant changes over the years: from 10% in 1990, to 2.5% in 2012, down to 0.01% in 2021, and then rising again with post-pandemic inflation.
Calculating Legal Interest: the Formula
The formula is the one given by the Italian Revenue Agency: interest = principal × legal rate × days / 36,500. The days are those between the start date and the end date. If the period spans more than one year, the calculation is split at 1 January and each part uses the rate of its year: the calculator does this for you and shows the detail period by period.
Worked Example
A principal of 5,000 euros from 1 July 2025 to 1 July 2026 (hypothetical example):
- from 1 July to 31 December 2025: 184 days at 2%, that is 5,000 × 2 × 184 / 36,500 = 50.41 euros
- from 1 January to 30 June 2026: 181 days at 1.60%, that is 5,000 × 1.60 × 181 / 36,500 = 39.67 euros
Total interest: 90.08 euros, which added to the principal makes 5,090.08 euros. With the same data the calculator gives the same result.
When Legal Interest Is Needed
- Civil lawsuits and payment orders: from the formal notice of default, interest accrues at the legal rate; from the moment the court claim is filed, if the parties had not set a rate, Article 1284, fourth paragraph, of the Civil Code applies the rate provided for late payments in commercial transactions (Legislative Decree 231/2002), which is higher. That part must be calculated separately
- Damage compensation: interest accrues on amounts awarded as damages from the date of the harmful event
- Inheritances and gifts: calculating legal interest is necessary to determine the present value of annuities and usufructs for tax purposes
- Late commercial payments: when Legislative Decree 231/2002 (default interest) does not apply, the legal rate is used
- Voluntary correction (ravvedimento operoso): the Italian Revenue Agency requires legal interest calculation to regularize late tax payments; for penalty and interest together there is the ravvedimento operoso calculator
How to Use the Calculator
Enter the principal amount (the sum on which to calculate interest), the start date (the day from which interest begins to accrue), and the end date (the day up to which to calculate). The calculator automatically applies the correct historical rates for each period, breaking down the calculation year by year when the period spans multiple years with different rates.
This is crucial because a manual calculation would require consulting the historical rate table and applying each rate pro-rata for the relevant period. Our tool performs everything automatically, ensuring precision to the cent.
Legal Interest Rates by Year
The rates set by the decrees of the Ministry of Economy (sources: Official Gazette, notes to Article 1284 of the Civil Code; Italian Revenue Agency for the years 2019 to 2026):
| Year | Annual legal rate |
|---|---|
| 2026 | 1.60% |
| 2025 | 2% |
| 2024 | 2.50% |
| 2023 | 5% |
| 2022 | 1.25% |
| 2021 | 0.01% |
| 2020 | 0.05% |
| 2019 | 0.80% |
| 2018 | 0.30% |
| 2017 | 0.10% |
| 2016 | 0.20% |
| 2015 | 0.50% |
| 2014 | 1% |
| 2012 and 2013 | 2.50% |
| 2011 | 1.50% |
| 2010 | 1% |
The calculator also contains the earlier years, back to 1942. The decree with the rate for the following year must be published in the Official Gazette by 15 December; if it is not published by then, the rate stays the same (Article 1284 of the Civil Code). Until the decree for 2027 is out, the calculator applies 1.60% to 2027 dates as well.
Difference Between Legal and Default Interest
It is important not to confuse legal interest with default interest. Default interest, governed by Legislative Decree 231/2002 for commercial transactions, has a significantly higher rate (ECB rate + 8 percentage points). Legal interest applies instead in private relationships and civil obligations when no contractual rate is specified.
Practical Tips
When preparing a summons or payment order, always specify the request for legal interest "from the date of formal notice of default until full payment." For voluntary tax corrections, remember that interest must be calculated day by day (pro-rata temporis) and paid together with the reduced penalty and the tax due. Our calculator is designed to provide results that can be used directly in court documents and tax computations, with period-by-period detail that you can attach as supporting documentation.
