Estimated calculation with current rates (late-payment surcharge 3.7% per month — effective 13 November 2025). Rates can change by Presidential Decree; the relevant authority's figure is authoritative. For informational purposes only.
Delay Period
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Late-Payment Surcharge
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Total Payable
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Number of Days
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Interest Amount
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Total Amount
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Frequently Asked Questions
The late-payment surcharge rate applied to tax and other public receivables is 3.7% per month as of 13 November 2025, per Presidential Decree No. 10556. This rate can be changed from time to time by a new Presidential Decree, which is why the rate field in this tool is left editable.
Under Article 51 of Law No. 6183 on the Collection Procedure of Public Receivables, the full monthly rate applies for each complete month, and for the remaining fraction of a month a daily rate (the monthly rate divided by 30) applies. For example, if a debt is 3 months and 15 days overdue: the rate × 3 for the 3 full months, plus (rate/30) × 15 for the 15 days, is applied to the principal.
Statutory interest is the rate applied to ordinary (non-commercial) receivables when the parties have not agreed on a rate, currently 24% per year. For receivables arising from commercial transactions between two merchants, the higher commercial default interest rate (currently 39.75% per year) applies once in default. The parties may also agree on a different rate by contract; in that case you can use the "Free rate" option in this tool.
This tool only provides a simple estimate. It does not account for special situations such as settlements, deferral/installment arrangements, offsetting, partial payments, interest-on-interest, or rounding differences in the administration's/court's own internal calculation procedures. For an exact and binding amount, refer to the relevant tax office/enforcement office or court record.
No. All calculations in this tool are done entirely in your browser with JavaScript — no amount or date is ever sent to OpenMoon's servers or anywhere else.
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