Loan Calculator
Enter the loan amount, annual rate and term — the monthly payment, total repayment and total interest appear right away. Calculated with the equal-payment method. Everything stays in your browser.
Examples (click to try)
How to Use the Loan Calculator
Enter the loan amount, annual rate and term to instantly see the monthly payment, total repayment and total interest under the equal-payment method. There is no button to press — the result updates live as you change any number, so it is ideal for tweaking the rate or term and comparing on the fly. The quickest start is to press one of the "Examples (click to try)" chips above, which fill in a mortgage, car or education-loan scenario and show the result right away.
- Enter the Loan Amount in yen (e.g. 30000000 for ¥30,000,000).
- Enter the Annual Rate as a percentage (e.g. 1.0).
- Enter the Term and choose the unit (years or months).
A Worked Example
For a loan of ¥30,000,000 at an annual rate of 1.0% over 35 years (420 payments), the monthly payment is about ¥84,686, the total repayment is about ¥35,567,998, and the total interest is about ¥5,567,998. Raise just the rate to 1.5% and the monthly payment climbs to about ¥91,855 while the total interest swells to about ¥8.58 million — a quick way to see how much the rate alone moves the total.
When This Helps
- Mortgages: Try different amounts, rates and terms to see what the monthly payment becomes.
- Car loans: Compare how much the total interest changes with a shorter or longer term.
- Refinancing: Check how much total interest a lower rate would save.
About the Equal-Payment Method
This tool uses the equal-payment method, where the monthly payment stays constant. The monthly rate is the annual rate divided by 12, and the number of payments is the term in months. The monthly payment is derived from the loan amount, monthly rate and number of payments; the total repayment is the monthly payment times the number of payments, and the total interest is the total repayment minus the loan amount. Rounding and fees are not included, so actual figures may differ slightly.
Amortization Formula
With principal P, monthly rate r = annual rate ÷ 12, and n payments, the level payment is P × r ÷ (1 − (1+r)^−n). At 0% interest it uses P ÷ n. Displayed payment, total, and interest values are rounded to yen.
Terms Not Modelled
The estimate assumes one fixed rate and equal monthly payments. It excludes variable or step rates, daily accrual, first/last-payment adjustment, extra and balloon payments, deferral, guarantees, origination fees, insurance, and taxes. Comparisons can also differ depending on whether a quoted rate is nominal or an effective APR.
Review the lender's amortization schedule and total cost before signing, and do not assess affordability from this estimate alone. Use Compound Interest for an investment-growth model.