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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₩80,000,000 Loan Interest (4% / 30yr) - Toolkit

For a ₩80,000,000 loan at 4% over 30 years (equal payment), the monthly payment is about ₩381,932 and total interest about ₩57,495,520.

2026Equal-payment (amortizing) formula

Loan principal

Annual rate (%)

Loan term (months)

Grace period (months, optional)

Monthly payment (first month)381,932

Total payments137,495,520

Total interest57,495,520

Interest calculationShow steps

Total interest57,495,520

Total payments − principal

= 137,495,520 − 80,000,000

Repayment schedule (first 12 payments)

No.	Payment	Principal	Interest	Balance
1	381,932	115,265	266,667	79,884,735
2	381,932	115,650	266,282	79,769,085
3	381,932	116,035	265,897	79,653,050
4	381,932	116,422	265,510	79,536,628
5	381,932	116,810	265,122	79,419,818
6	381,932	117,199	264,733	79,302,619
7	381,932	117,590	264,342	79,185,029
8	381,932	117,982	263,950	79,067,047
9	381,932	118,375	263,557	78,948,672
10	381,932	118,770	263,162	78,829,902
11	381,932	119,166	262,766	78,710,736
12	381,932	119,563	262,369	78,591,173

Showing only the first 12 payments of the full term.

How it's calculated & notes

·With equal-payment repayment the monthly amount stays constant; with equal-principal repayment the principal portion is constant, so interest gradually decreases.
·During the grace period you pay interest only and the principal stays unchanged; after it ends, the principal is repaid over the remaining term. A longer grace period increases total interest.
·Actual loans may differ in total interest depending on prepayment fees, variable rates, and day-count conventions.
·This calculator provides an estimate assuming a fixed rate and equal monthly repayment.

Repayment Analysis for a ₩80,000,000 Loan

Borrowing ₩80,000,000 at 4% for 30 years (equal payment) gives a monthly payment of about ₩381,932, total interest of about ₩57,495,520, and total repayment of about ₩137,495,520.

Repayment summary

Monthly payment: ₩381,932
Total interest: ₩57,495,520
Total repayment: ₩137,495,520

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 {rate}% over {years} years.

Repayment methods

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

View the full loan interest table →

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.

Last updated: July 2026 · Sources: 한국은행