How will the Bank of Japan's interest rate hike affect home loans? Simulating interest rate increases for a 6 million yen annual income and a 45 million yen loan

Thank you for your response to my previous article. I hope it reached those who were searching for answers due to the same anxieties. For those who weren’t, I imagine this topic is a concern for many people.

The Bank of Japan recently held a Monetary Policy Meeting. I suspect many of you saw the news and wondered, “Is my loan going to be okay?”

Here is the conclusion first: there is no need to panic, but it is reassuring to take a look at the numbers once.

What was decided at the October 30th Bank of Japan meeting?

There are two main points.

• The policy interest rate remains unchanged at 1.25% (no rate hike).

• The Bank of Japan stated that the underlying trend of inflation has reached a “level generally consistent” with its 2% target.

In other words, interest rates did not rise this time. This does not mean your home loan repayments will change immediately.

However, the Bank of Japan has acknowledged that prices are approaching their target. It is expected that the trend of gradually adjusting interest rates will continue in the future.

★Furthermore, Governor Ueda explained cautiously at the press conference that “this is not a declaration that the target has been achieved sustainably and stably.” It has not been decided when or by how much they will move next.

What is important is not to be swayed by every piece of news, but to know in advance “what will happen to my household finances if interest rates move.”

Monthly repayments by interest rate for a 6 million yen annual income and a 45 million yen loan

So, how do repayments change when interest rates move?

This is for a case with an annual income of 6 million yen, a loan of 45 million yen, a 35-year term, and equal principal and interest payments.
(Estimates, no down payment, fixed-rate for the entire period)

• 1.0% interest rate: approx. 127,000 yen per month (repayment burden ratio approx. 25%)

• 1.5% interest rate: approx. 138,000 yen per month (repayment burden ratio approx. 28%)

• 2.0% interest rate: approx. 149,000 yen per month (repayment burden ratio approx. 30%)

• 2.5% interest rate: approx. 161,000 yen per month (repayment burden ratio approx. 32%)

★For every 0.25% increase in interest rates, monthly repayments are calculated to increase by approximately 5,000 to 6,000 yen. A 1% increase results in an increase of approximately 22,000 yen.

Generally, it is said that a repayment ratio of within 25% is safe, and exceeding 30% leaves little room in the household budget.

Variable interest rates are easily influenced by policy rates, while fixed interest rates are determined with reference to long-term interest rates. The way you are affected depends on which one you choose.

Whether it is ‘reckless’ or not is determined not by the 45 million yen amount, but by what your household situation is like when the interest rate is at a certain percentage.

What is easy to overlook is what is ‘outside’ the repayment amount

The figures up to this point only concern the loan. In an actual household budget, expenses such as the following will also arise.

• Children are born and education expenses increase

• There is a lump-sum expense in the year of university enrollment

• Car replacements and home repairs occur

• Income decreases after retirement, but the loan remains

★ Even if the repayment amount is an ‘affordable amount,’ there may be a single year where you run out of cash.

If you know this in advance, you can prepare for it. Having a clear outlook is the best source of peace of mind.

Therefore, please make your own judgments.

I have had the same anxieties and have verified them many times using Excel and Python. ‘Mirai Note’ is what I created to make that possible on a smartphone.

• Enter home purchases, childbirth, university enrollment, retirement, etc., and view your assets and liabilities for up to 60 years in the future on a graph

• It evaluates the health of your household budget with a score

• It even provides specific improvement amounts, such as ‘If you cut back on dining out by 15,000 yen per month, you will have +8.05 million yen at age 65’

• No registration required, and all data is stored only on your own device (it is not sent externally)

At this timing when interest rate news has come out, if you check ‘what will happen in my case,’ you will be able to view future news calmly.

The reason I want you to try it now

It is currently a beta version released for free. The feedback I receive is directly reflected in the next update.

★Now is the only time you can tell us about usability issues or missing features.

You can try it in 3 minutes. Please give it a try.

▼Try Mirai Note (Free, no registration required)
https://mirai-note-b25e6.web.app

Please let us know your thoughts or requests in the comments section or on X (Twitter).

▼Click here for the previous article
“A 45 million yen home on a 6 million yen household income. Is this reckless?”
(<iframe class=”note-embed” src=”https://note.com/embed/notes/n058ed561541d” style=”border: 0; display: block; max-width: 99%; width: 494px; padding: 0px; margin: 10px 0px; position: static; visibility: visible;” height=”400″></iframe><script async src=”https://note.com/scripts/embed.js” charset=”utf-8″></script>)

---

*This article is a general simulation based on information as of November 1, 2026. Actual repayment amounts vary depending on the financial institution, product, and terms. For individual consultations, please contact a financial institution or a financial planner.

Reference Links

#HomeLoan #BankOfJapan #InterestRateHike #MyHome #LifePlan #HouseholdBudgetManagement