Mortgage Calculator

Japanese mortgages offer two main repayment methods: equal payment (元利均等), where each payment is the same amount, and equal principal (元金均等), where the principal portion is fixed and interest decreases over time. Additionally, bonus payments (ボーナス払い) — extra semi-annual payments — are common in Japan. This tool lets you input all these conditions to simulate monthly payments, bonus payments, total repayment, and total interest in real time.

When you select equal principal, the tool displays the first and last month payments separately, helping you understand payment fluctuations over the loan term. An annual repayment schedule table shows year-by-year principal, interest, and remaining balance — giving you a complete overview of your loan progression. Preset loan amounts (30M/40M/50M JPY) allow quick multi-scenario comparison.

This tool also supports Japan's Housing Loan Tax Deduction (2024+), allowing you to select housing types (new certified, ZEH-standard, energy-efficient, or used housing) and automatically calculate deductible loan amounts and cumulative tax benefits over 13 years (or 10 years for used housing). The effective payment after tax deduction is displayed, making the financial impact of tax incentives immediately clear. Perfect for comprehensive home purchase planning and mortgage comparison. Runs entirely in your browser with no server data transfer.