We have added a new 'Policy Rate-Linked Mortgage Simulator' to our Income Calculator web app (https://tedorikeisan.com/mortgage-policy-rate). Since ending negative interest rates in March 2024, the Bank of Japan has raised its policy rate to 1.25% as of September 2026. We built this feature in response to many homeowners with variable-rate mortgages asking when, and by how much, their payments will rise.
Key Features:
With a variable-rate mortgage, the 5-year rule keeps payments unchanged even after rates rise, while principal quietly shrinks more slowly. Use this feature to understand your current rate and your next payment revision, and to consider prepayment or refinancing.
The Income Calculator web app remains free to use. The same feature is planned for the mortgage calculator app 'MORA' in its next update.