This simulation assumes a dual-income Yokohama household in its 30s with gross monthly income of ¥690,000 and a ¥45 million mortgage. These figures are not averages for Yokohama households. The model is designed to show sensitivity to fixed costs: at mortgage rates from 1% to 3%, the monthly payment changes from about ¥127,000 to ¥173,000.
Assumptions for a dual-income Yokohama household in its 30s
| Item | Assumption | Treatment |
|---|---|---|
| Husband's monthly income | ¥370,000 | Simulation assumption |
| Wife's monthly income | ¥320,000 | Simulation assumption |
| Gross household monthly income | ¥690,000 | Combined income of two people |
| Mortgage principal | ¥45 million | Assumption, not an average home price |
| Repayment period | 35 years | Equal principal-and-interest payments; no bonus payments |
A 1-percentage-point rate change can alter monthly payments by around ¥20,000
For a ¥45 million mortgage over 35 years with equal principal-and-interest payments and no bonus payments, the approximate repayments are as follows.
| Annual interest rate | Approx. monthly payment | Share of ¥690,000 gross monthly income |
|---|---|---|
| 1.0% | About ¥127,000 | About 18.4% |
| 2.0% | About ¥149,000 | About 21.6% |
| 3.0% | About ¥173,000 | About 25.1% |
From 1% to 3%, monthly repayment rises by about ¥46,000, or roughly ¥550,000 per year. Household room depends not only on the home price but also on the interest rate, down payment, management fees, repair reserves, and property tax.
In Yokohama, rail line and station distance can change both housing costs and commuting time
Aoba, Tsuzuki, and Kohoku, as well as areas along the Toyoko and Den-en-toshi lines, offer convenient access to Tokyo but tend to have higher housing costs. Moving farther into the suburbs can reduce housing costs, while potentially increasing commuting time or spending on cars and buses.
For dual-income households in their 30s, childcare, education costs, shorter working hours, or a temporary leave of absence by either partner can also materially change the budget. Rather than relying on Yokohama-wide averages, it is more practical to stress-test the household using the actual rail line, workplace, and childcare conditions involved.
How to read this simulation
This simulation is a fixed-condition example, not a published average for home prices or household income. Repayment amounts are approximate. The calculation does not include take-home pay, taxes, social insurance, management fees, repair reserve contributions, property tax, or education expenses. A formal calculation from a financial institution is necessary before making a purchase decision.
Summary: For households in their 30s, test resilience to fixed costs rather than relying on average income
With assumed gross monthly income of ¥690,000 and a ¥45 million mortgage, the repayment ratio moves from about 18% to 25% as the interest rate rises from 1% to 3%. Whether buying in Yokohama is sustainable should be judged by whether the household can withstand higher rates, shorter working hours, and education costs—not by average income alone.
- At 1%: about ¥127,000 per month
- At 2%: about ¥149,000; at 3%: about ¥173,000
- Moving from 1% to 3% adds about ¥550,000 a year in repayments
- Use the actual rail line, station distance, and ability to maintain dual incomes
Source: Published statistics listed in the Analysis notes at the end of this article
📊 Analysis notes
This article is based on the following statistical data.
- Statistics used:
- Statistics Bureau of Japan, National Survey of Family Income, Consumption and Wealth (Household Assets) (Table ID: 0003426527, view on e-Stat)
- Statistics Bureau of Japan, National Survey of Family Income, Consumption and Wealth (Household Income) (Table ID: 0003426439, view on e-Stat)
- Area: Yokohama
- Data retrieved: June 6, 2026
- Notes: The article is organized primarily around published statistical figures. Because asset distributions, household differences, and other factors outside the article also matter, numerical values directly observable in the statistical tables should be distinguished from interpretation.
Chart and table values have been independently aggregated and visualized from the statistical data above.
Table values have been organized from the statistical data above.