Money

Home Loan Calculator

Enter the loan amount, interest rate, and loan term to calculate the monthly payment, total repayment, and total interest. Supports the equal principal-and-interest repayment method.

Loan Amount
JPY
Interest Rate (Annual)
%
Loan Term
years
Monthly Payment
{{ fmt(result.monthly) }} JPY
Total Repayment
{{ fmt(result.total) }} JPY
Total Interest
{{ fmt(result.interest) }} JPY
Year Annual Payment Principal Interest Remaining Balance
{{ row.year }} {{ fmt(row.payment) }} {{ fmt(row.principal) }} {{ fmt(row.interest) }} {{ fmt(row.balance) }}

Tips

  • This calculator uses the equal principal-and-interest method, where the monthly payment remains constant throughout the loan term.
  • Be sure to check whether your loan uses a fixed rate or a variable rate. Variable rates may cause your payment to change over time.
  • Extending the loan term lowers your monthly payment, but increases the total interest paid significantly.
  • In Japan, a mortgage tax deduction (住宅ローン控除) may allow you to reduce your income tax based on the outstanding loan balance — check eligibility conditions.
  • A common guideline is to keep your repayment ratio (annual repayment ÷ annual income) within 25–35%.

Frequently Asked Questions

Equal principal-and-interest repayment (the most common method) keeps your monthly payment fixed throughout the loan term, making budgeting straightforward. Equal principal repayment starts with higher payments that gradually decrease; under the same conditions, it results in less total interest paid. Japanese home loans (住宅ローン) typically use equal principal-and-interest repayment.

Variable rates are currently lower (around 0.3–1.0% per year in Japan) and reduce monthly payments, but carry the risk of rate increases. Fixed rates (such as Flat 35) lock in your payment amount for certainty, though the initial rate is somewhat higher. The right choice depends on your financial buffer and your outlook on future interest rate movements.

The earlier, the more effective. Making a lump-sum prepayment early in the loan — when the outstanding balance is large — eliminates more of the future interest. There are two types: term-shortening (reduces the remaining loan period) and payment-reduction (lowers the monthly payment). The term-shortening option generally saves more in total interest.

You can deduct 0.7% of the year-end loan balance from your income and residence taxes for up to 13 years. For example, with a balance of 30 million JPY, the maximum annual deduction is 210,000 JPY. If the deduction exceeds your income tax liability, a portion is also applied to residence tax.

The repayment ratio — annual repayment divided by annual income — is generally recommended to stay within 25–35%. For an annual income of 5 million JPY, that means annual repayments of 1.25–1.75 million JPY (roughly 104,000–146,000 JPY per month). Many lenders use 30–35% as their upper limit for loan approval.

Side Note — The Mystery of the "35-Year" Home Loan

In Japan, the most common home loan term is 35 years. This originated from post-war housing finance policies, where long repayment periods were introduced to make home ownership accessible to more people.

For example, borrowing 30 million JPY at 1.5% over 35 years results in a monthly payment of approximately 91,900 JPY, with roughly 8.58 million JPY in total interest — about 28.6% on top of the principal.

If your income drops or interest rates rise mid-loan, your financial situation can become strained. Keeping a buffer in your monthly budget is always a wise strategy.

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