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Melikhan ÖzçelikCertified Public Accountant (SMMM)

Late payment surcharge calculator

Late payment surcharge and default interest on Turkish tax debts at the current monthly rate under Law No. 6183 Art. 51.

Late payment surcharge and interest

Law No. 6183 Art. 51 and Tax Procedure Law (VUK) Art. 112. Partial months are calculated by days.

If the delay spans more than one rate period, calculate each period separately.
Principal
100,000.00 TL
Delay
4 months 12 days
Daily rate
0.1233%
Late payment surcharge
16,280.00 TL
Total payable
116,280.00 TL

Calculations are for general information only. Rates and amounts are current as of November 2026; always check current legislation before filing or paying.

How is late payment interest calculated?

A monthly rate of late payment interest (gecikme zammı) is applied to public receivables that are not paid on time, for each month starting from the due date. Any incomplete month is taken into account on a daily basis: the monthly rate is divided by 30 to obtain a daily rate, which is then multiplied by the number of remaining days. The formula is: principal × monthly rate × (full months + days / 30). Late payment interest is applied only to the principal debt; no further late payment interest is charged on the interest itself.

Legal basis and rates

Late payment interest is governed by Law No. 6183 on the Collection Procedure of Public Receivables, Article 51, and its rate is set by Presidential Decree. From 13.11.2025 the monthly rate is 3.7%; between 21.05.2024 and 12.11.2025 a rate of 4.5% applied. Default interest (gecikme faizi), on the other hand, is calculated under Article 112 of Tax Procedure Law No. 213 (VUK) on taxes assessed additionally, ex officio or administratively, for the period between the original due date and the date of accrual, at the late payment interest rate. If the period spans more than one rate period, each period should be calculated separately at its own rate and the results added together.

Worked example

If a tax debt of 100,000 TL is paid 4 months and 12 days late, entirely within the period subject to the 3.7% rate, the late payment interest is 100,000 × 0.037 × 4.4 = 16,280 TL. The total amount payable is 116,280 TL. The daily rate is approximately 0.1233%. Here, the 12 days are converted into 0.4 of a month (12 / 30) and added to the 4 full months.

For tax and penalties based on a notice of assessment, you can review the payment options in the scenario comparison on the tax disputes page.

Frequently asked questions

What is the difference between late payment interest and default interest?

Late payment interest (gecikme zammı) accrues on public receivables not paid on time, starting after the due date (Law No. 6183, Article 51). Default interest (gecikme faizi) is calculated on taxes assessed later, for the period between the original due date and the accrual date (VUK Article 112).

How is it calculated when the rate changes?

Each rate applies only to the period during which it is in force. The period is split in two, each part is calculated at its own rate and the results are added together.

How are partial months taken into account?

For an incomplete month, the monthly rate is divided by 30 to obtain a daily rate, which is multiplied by the number of days of delay.

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