Equal payment vs equal principal?

Equal payment keeps the monthly amount constant; equal principal has a higher early payment but lower total interest.

What rate and term does this assume?

This page assumes 4.0% over 30 years (360 months), equal payment. Change the rate and term in the calculator.

Does early repayment reduce interest?

Yes — repaying principal early reduces the remaining interest, though early-repayment fees may apply.

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ローン利息計算機

元利均等・元金均等返済シミュレーション

2026年元利均等返済の計算式

借入元金

年利率 (%)

借入期間 (ヶ月)

据置期間 (ヶ月、任意)

What is the loan interest calculator?

The loan interest calculator computes the monthly payment and total interest from the principal, annual rate, and term. Equal payment keeps the monthly amount constant; equal principal repays a fixed principal each month, with a higher early burden but less total interest. This page assumes 4% over 30 years.

Repayment methods

Equal payment: same monthly amount
Equal principal: same principal, declining interest
Rate and term greatly affect total interest

Frequently Asked Questions

Equal payment vs equal principal?: Equal payment keeps the monthly amount constant; equal principal has a higher early payment but lower total interest.
What rate and term does this assume?: This page assumes 4.0% over 30 years (360 months), equal payment. Change the rate and term in the calculator.
Does early repayment reduce interest?: Yes — repaying principal early reduces the remaining interest, though early-repayment fees may apply.

Calculation software reviewed: 2026-10-22. Principal, annual rate, term and grace period are user inputs; this tool does not retrieve Bank of Korea rate data or lender quotes.

Monthly rate r=annual rate÷100÷12; repayment term n=total months−grace months. Equal payment=P×r×(1+r)^n÷((1+r)^n−1), or P÷n at 0%. Equal principal adds balance interest to P÷n. Grace months pay interest only. Amounts round to whole won and the last instalment settles the balance. Fees and daily accrual are excluded; actual contracts may differ.