Interest Calculator
Statutory, commercial and contractual interest
Calculate interest on a debt in Turkish lira from the date of default until payment. Choose statutory interest, commercial default interest at the CBRT advance rate, or a fixed contractual rate; rate changes are applied period by period.
For information only, based on the law and published rates on the calculation date; it is not legal advice. Calculations powered by Emsal AI.
Which rate applies
Statutory and default interest are governed by Law No. 3095 on Legal Interest and Default Interest. In commercial matters, default interest follows the advance interest rate of the Central Bank of the Republic of Türkiye (CBRT). The calculator splits the period at every rate change and adds up the interest for each part.
Using the interest calculator
This calculator calculates accrued interest using the principal, dates and interest type entered. Read the interest amount separately from the principal. Whether the selected interest type applies to the debt requires a separate legal assessment.
Enter the amount in Turkish lira under “Principal (TRY)”. Use “Interest runs from” for the default or due date and “Until” for the end date. The starting day is excluded and the ending day is included.
Under “Interest type”, choose “Statutory interest”, “Commercial default interest (CBRT advance rate)” or “Contractual rate”. Selecting “Contractual rate” displays the required “Annual contractual rate (%)” field. The contract must also be examined when assessing the result.
Check the principal and both dates.
Select the interest type according to the debt and the contract.
Review the dates, day counts and rates together.
Simple interest and changes in rates
The calculator uses simple interest: principal × annual interest rate × number of days ÷ 365. Convert a percentage rate to its decimal equivalent for multiplication. The denominator remains 365 even in a leap year.
If a rate changes during the selected interval, the calculation is divided into periods at the relevant effective dates. Each period uses the same principal, the applicable annual rate and its own day count. The period amounts are added to give total accrued interest.
Interest from an earlier period is not added to the principal for the next period. The latest rate is not applied retrospectively to earlier days.
Statutory interest rates and reference dates
Statutory interest is referred to in Turkish as both kanuni faiz and yasal faiz. Under the Law on Statutory Interest and Default Interest (Law No. 3095), the annual rate is 9% from 1 January 2006 to 31 May 2024. From 1 June 2024 to 30 July 2026, it is 24% under Presidential Decision No. 8485.
From 31 July 2026, the method introduced by Law No. 7589 uses 80% of the rediscount rate applied to short-term credit transactions by the Central Bank of the Republic of Türkiye (CBRT) on 31 December of the preceding year. The rediscount rate is the reference rate used to calculate the statutory interest rate.
If the rediscount rate on 30 June differs from the preceding 31 December rate by at least 5 percentage points, 80% of the 30 June rate applies in the second half of the year. Both the reference date and the size of the change matter.
Commercial default interest and calculation limits
Under Article 2(2) of Law No. 3095, statutory interest applies to commercial transactions where the contract contains no interest rate. However, if the CBRT short-term advance rate on 31 December of the preceding year exceeds the statutory interest rate, that advance rate may be claimed. The advance rate is distinct from the rediscount rate used in the statutory interest method.
Commercial default interest also has a rule concerning a change of 5 percentage points as at 30 June. The contract must be examined alongside the reference dates and rates. Selecting “Commercial default interest (CBRT advance rate)” does not establish whether the debt is commercial or whether a contractual provision applies.
The calculator does not compound interest. Article 121 of the Turkish Code of Obligations prohibits interest on interest, subject to the exception for commercial transactions under Article 8 of the Turkish Commercial Code. Whether that exception applies requires separate examination. The Code of Obligations provisions on performance and default include Article 121.
The calculator does not calculate statutory interest for periods before 1 January 2006 or commercial default interest for periods before 2023. It produces no result for a period dependent on a CBRT rate that is not yet known. A known rate is not carried forward into such a period. The calculation is for information only.
Example: statutory interest across a rate change
Enter TRY 100,000.00 in “Principal (TRY)”, 30 June 2026 in “Interest runs from” and 31 August 2026 in “Until”. Select “Statutory interest”. The first counted day is 1 July 2026 because the starting day is excluded.
For 1–30 July 2026, there are 30 days at 24%: TRY 100,000.00 × 0.24 × 30 ÷ 365 = TRY 1,972.60. For 31 July–31 August 2026, there are 32 days at 31%: TRY 100,000.00 × 0.31 × 32 ÷ 365 = TRY 2,717.81.
The 31% rate is 80% of the 38.75% rediscount rate on 31 December 2025. Total accrued interest is TRY 1,972.60 + TRY 2,717.81 = TRY 4,690.41. The commercial advance rate given for 2026 is 39.75%; it relates to the separate commercial default interest option.
Frequently asked questions
Are yasal faiz and kanuni faiz the same?
On this page, both expressions mean statutory interest. Commercial default interest is a separate option. A higher result alone does not justify selecting it without examining the contract and the nature of the debt.
Are the starting and ending days included?
The day entered under “Interest runs from” is excluded; the day entered under “Until” is included. Where rates change, the counted days are allocated to the corresponding periods.
Does the calculator always divide by 365?
Yes, including in leap years. Each period’s interest is calculated using the principal, annual rate and counted days, with 365 as the denominator.
When can the commercial advance rate be used?
For commercial transactions without a contractual interest rate, the relevant CBRT advance rate may be claimed if it exceeds the statutory interest rate. The reference dates, June change rule and contract must also be considered.
Can I obtain a definite interest figure for a future date?
If the period depends on a CBRT rate that is not yet known, the calculator produces no result for that period. Applying an existing rate to that period would not establish a definite amount.