참고법Legal & Tax Calculators
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The calculation you need, step by step

Interest rate limit calculator

Check excess interest and principal allocation at a single final settlement.

Information needed

Enter amounts in Korean won (KRW), without commas. Do not enter names or resident registration numbers.

After changing an entry, calculate again. This calculator does not transmit or store your entries.

Reference results

Check the entries, then select Calculate.

Formula and scope

For ordinary loans entered/renewed from 7 July 2021, the maximum annual rate is 20%. Compare contractual and capped interest as original principal × annual rate × days ÷ 365. Paid interest above the lawful amount first reduces outstanding principal; only the balance after principal is extinguished is shown as potentially returnable.

What this calculator cannot apply

Only loans of at least KRW 100,000 with no interim repayments and one final settlement. Excludes prepaid interest, fees, compounding, payment allocation disputes, older contracts, registered lenders and financial institutions. If principal was separately paid on the final day, enter its balance immediately afterwards. No determination of restitution rights/limitation periods. Not a late-payment damages calculator.

Calculation basis and official sources

Sources checked: 8 November 2026 (KST, Asia/Seoul)