How are Japanese personal loan repayments calculated?

The tool uses the standard amortising loan formula. The monthly rate is the annual rate divided by 12, and the payment is the principal times the monthly rate times (1 plus the monthly rate) to the power of the number of months, divided by that same factor minus one. Each month interest is charged on the outstanding balance and the rest of the payment reduces the principal.

What is the legal interest rate cap in Japan?

The Interest Rate Restriction Act (利息制限法) caps annual interest at 20% for loans under ¥100,000, 18% for ¥100,000 to ¥1,000,000, and 15% for ¥1,000,000 and above. Interest charged above the applicable cap is legally unenforceable, and the tool flags any rate that breaches it.

What rates do Japanese personal loans actually charge?

Bank card loans (カードローン) and unsecured personal loans typically range from about 2% to 14.6% per year. Larger loans and stronger borrowers get lower rates. Consumer-finance lenders sit at the higher end, close to the statutory ceiling.

Does this include fees or revolving balances?

No. It models a fixed-rate, fixed-term instalment loan with equal monthly payments. Revolving card-loan balances, add-on interest, guarantee fees and early-repayment charges are not included, so treat the result as the core interest cost.

How can I pay less interest?

Borrow less, choose a shorter term, or secure a lower rate. A shorter term raises the monthly payment but cuts total interest sharply. Making extra repayments against the principal early in the schedule has the biggest effect because interest is charged on the outstanding balance.

Japan Personal Loan Calculator

Email me this result

Get this tool's output sent to your inbox, plus one useful tool a week. No spam, unsubscribe any time.

A Japan personal loan calculator that turns a loan amount, rate and term into your monthly repayment, total interest and a full amortisation schedule — and warns you if the rate breaches Japan’s statutory interest caps.

How it works

Repayments use the standard amortising loan formula:

M = P * r * (1 + r)^n / ((1 + r)^n - 1)

where P is the loan, r is the monthly rate (annual rate divided by 12) and n is the number of months. Each month, interest is charged on the outstanding balance, and whatever is left of the payment reduces the principal — so early payments are mostly interest and later ones mostly principal.

The tool also checks the Interest Rate Restriction Act (利息制限法) ceiling for your loan size:

under ¥100,000 → 20%
¥100,000–¥1,000,000 → 18%
¥1,000,000 and above → 15%

Interest above the applicable cap is unenforceable in Japan, so any breaching rate is flagged.

Example and notes

Borrow ¥1,000,000 at 9.5% over 5 years. The monthly repayment is about ¥21,000, and the amortisation table shows interest shrinking and principal growing each month until the balance reaches zero. Because the loan is ¥1,000,000, the statutory cap is 15%, so 9.5% is well within the limit.

This is an estimate for a fixed-rate instalment loan. It ignores guarantee fees, revolving balances and early-repayment charges. All figures are calculated locally in your browser.