Financial Tools

Loan Interest Calculator

Calculate monthly payments and total interest before you borrow.

KRW
%
yr

Pay the same total (principal + interest) each month.

Est. Monthly Payment

0 KRW
Total Interest0 KRW
Total Payment0 KRW

💡 Repayment Tips

Generally, Equal Principal costs the least in total interest. Equal P+I offers predictable payments and easier budgeting.

About the Loan Calculator

Calculate your monthly payment and total interest for Equal P+I, Equal Principal, and Bullet repayment methods.

Repayment Methods

  • •Equal P+I: Same payment every month. Easy to budget, but interest-heavy early on.
  • •Equal Principal: Same principal every month; interest declines. Lowest total interest.
  • •Bullet: Interest only, then full principal at maturity. Low monthly cost, large lump-sum at end.

How to Use

  1. 1.Enter the loan amount (e.g., ₩100M).
  2. 2.Enter the annual interest rate (e.g., 4.5%).
  3. 3.Enter the loan period (e.g., 30 years).
  4. 4.Choose a repayment method.
  5. 5.View monthly payment, total interest, and total payment.

Important Notes

  • •This calculator is for reference only. Actual loans may include additional fees or insurance.
  • •Rates may change; verify the current rate at the time of borrowing.
  • •Plan repayments based on your income and expenses before borrowing.
  • •Compare multiple lenders to find the best terms.

Complete Guide to Loan Interest

Differences by Repayment Method

There are three main loan repayment methods, each with distinct characteristics affecting your monthly payments and total interest.

  • Equal Principal & Interest (Amortization): Same monthly payment throughout. Easy to budget, but you pay more total interest. Most common for mortgages.
  • Equal Principal: Fixed principal portion each month with decreasing interest. Payments start higher but decrease over time. Lower total interest than amortization.
  • Bullet Repayment: Pay only interest monthly, then repay the entire principal at maturity. Lowest monthly payments but highest total interest.

Example: On a $100,000 loan at 4% for 30 years, equal P&I pays about $71,870 in total interest, while equal principal pays about $60,167 — a difference of over $11,000.

What are DTI and DSR?

DTI (Debt-to-Income Ratio) measures how much of your annual income goes toward debt repayment. DSR (Debt Service Ratio) is stricter — it considers all existing loan repayments, not just the new loan.

Korean banks typically require DSR below 40-50% for mortgage approval. For example, if your annual income is $50,000 and total annual loan payments are $20,000, your DSR is 40%. Understanding these ratios helps you estimate your maximum borrowing capacity.

Tips to Save on Loan Interest

  • Compare rates across lenders: Interest rates can vary by 0.5-1%p between banks. Use comparison platforms to find the best deal.
  • Consider prepayment: If you have extra funds after the prepayment penalty period (usually 3 years), paying off principal early can save significant interest.
  • Use online/mobile channels: Many banks offer 0.1-0.3%p rate discounts for loans applied through internet or mobile banking.
  • Maintain a good credit score: A higher credit score qualifies you for lower interest rates. Pay bills on time and manage your credit utilization.

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