Japan Mortgage Calculator
Your loan
Pre-filled estimate: central-bank rate 1.25% plus a typical lender margin. Replace it with your lender's offer.
- Principal & interest¥105,871
Upfront costs
- Down payment¥4,000,000
- Closing costs%¥2,800,000
- Cash needed at purchase¥6,800,000
What if interest rates change?
Your payment today is just the start. See how it could move if rates go up or down during your loan.
Range: 1.19% to 1.31% · The rate resets once a year.
Likely range of your monthly payment
- Most likely
- 80% of outcomes
- Middle 50% of outcomes
- If today's rate holds
In 8 out of 10 simulated futures, you pay between ¥8,303,456 and ¥8,628,955 in total interest (today's rate: ¥8,465,846).
| Scenario | Avg. monthly | Highest monthly | Total interest | vs. today |
|---|---|---|---|---|
| Rate stays at 1.25% | ¥105,871 | ¥105,871 | ¥8,465,846 | — |
| Drops to 1.19% at first reset | ¥104,857 | ¥105,871 | ¥8,039,908 | ▼ −¥425,937 |
| Rises to 1.31% at first reset | ¥106,891 | ¥106,921 | ¥8,894,379 | ▲ +¥428,533 |
| Climbs steadily to 1.31% | ¥106,213 | ¥106,411 | ¥8,609,333 | ▲ +¥143,487 |
| Falls steadily to 1.19% | ¥105,530 | ¥105,871 | ¥8,322,776 | ▼ −¥143,070 |
| Spikes to 1.31% for 3 years | ¥106,037 | ¥106,921 | ¥8,535,466 | ▲ +¥69,620 |
Based on 600 simulated rate paths that drift randomly within your range and tend back toward today's rate. This is an illustration, not a forecast.
Loan balance over time
- Remaining balance
- Interest paid (cumulative)
- Principal paid (cumulative)
Interest rates in Japan
Monthly averages. Sources: Bank for International Settlements
Shows the central-bank policy rate. Mortgage rates are usually higher.
Buying a home in Japan: rules and costs
- Most borrowers choose variable-rate loans; Flat 35 offers fixed rates for up to 35 years.
- Purchase costs (brokerage, registration tax, stamp tax, acquisition tax) are typically 6–8% for existing homes and lower for new ones.
- The housing loan tax credit can reduce income tax by a share of the year-end loan balance.
Sources: Japan Housing Finance Agency (Flat 35) · Rules last reviewed 2026-10.
Frequently asked questions
How is the monthly mortgage payment calculated?
For an equal-payment loan, the payment is P × i × (1 + i)^n ÷ ((1 + i)^n − 1), where P is the loan amount, i the monthly interest rate and n the number of months. Taxes, insurance and fees are added on top.
What is the current average mortgage rate in Japan?
Japan does not publish an official average mortgage rate that we can track. Ask several lenders for quotes and enter the rate in the calculator.
How much does a 1-point rate rise change my payment?
On a ¥36,000,000 loan over 35 years, going from 1.25% to 2.25% raises the monthly payment from ¥105,871 to ¥123,925 — about ¥18,054 more each month.
What upfront costs should I budget for in Japan?
On a ¥40,000,000 purchase, expect about ¥2,800,000 in taxes and fees on top of your down payment. The breakdown is shown in the calculator above.
Can this calculator predict future interest rates?
No. The scenario tool shows a range of possible outcomes based on the band you choose. Nobody can predict rates reliably — use it to check whether you could still afford the loan if rates rise.