🧮 Calculators & Daily Life

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.

  1. Enter the Loan Amount in yen (e.g. 30000000 for ¥30,000,000).
  2. Enter the Annual Rate as a percentage (e.g. 1.0).
  3. 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.

Frequently Asked Questions

Is my data sent to a server?
No. All calculations happen entirely in your browser. The loan amount, rate and term you enter are never transmitted to or stored on any external server. You can use this tool with complete confidence.
What is the equal-payment method?
It is a repayment method where the monthly payment (principal plus interest) stays constant for the entire term. It is the most common structure for mortgages and car loans. Early payments are weighted toward interest, and the principal portion grows over time. This tool uses this equal-payment method.
Will the result match my actual payments?
It is an estimate. Real loans can differ due to rounding, bonus or balloon payments, guarantee fees and processing charges, and variable interest rates. Use it as a guide before you borrow.