(BOJ Rate Hike) Real-time record of mortgage repayments and interest rate fluctuations

At the Monetary Policy Meeting held on September 18, 2026, the Bank of Japan decided to raise the policy interest rate from the previous 1.00% to 1.25%. I also received an email from SBI Shinsei Bank regarding the mortgage interest rate hike for my joint loan. 😭

Before the interest rates rose, I made a last-minute early repayment of my mortgage, so I am keeping a record of the actual figures and the savings effect.
Also, in preparation for future interest rate fluctuations, I have set up this article to be updated with a ‘Record of Interest Rate and Early Repayment Amount Trends’ at the end.

Before and After Early Repayment
For this early repayment, I chose to ‘keep the monthly repayment amount the same and shorten the repayment period (period reduction type).’

Two effects achieved this time

1. Repayment period moved forward by ’10 months’
By making an early repayment of approximately 285,000 yen, the completion date changed from November 2046 to January 2046.
I was able to skip the ‘last 10 months’ of payments 20 years from now all at once.

2. Interest savings effect is approximately 100,000 to 110,000 yen
The monthly repayment amount for 10 months (31,978 yen x 10 months = 319,780 yen) will be waived.
When combining the difference from the principal invested (285,517 yen) and the reduction in future interest generated by the lower principal, the total interest saved is calculated to be approximately 100,000 to 110,000 yen.
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Record of Interest Rate and Early Repayment Amount Trends (Updated as needed)
I will add records here as needed whenever there are future interest rate hikes, revisions, or additional early repayments.
As of October 2026 (Baseline data)
* Interest rate: 0.690%
* Balance: 6,919,617 yen
* Monthly repayment amount: 31,978 yen
* Scheduled completion: January 26, 2046
* Memo: Period reduction type early repayment (285,517 yen) completed.