Mortgage Calculator Repayment Simulator App

The biggest source of anxiety about home loans is not being able to see the full picture of the large numbers involved—"How much do I pay each month?" and "How much will I end up paying in total?" This app lets you enter just the loan amount, interest rate, and repayment period, and instantly displays your monthly payment, total repayment amount, and total interest. It transforms vague worries into clear numbers, allowing you to calmly plan your finances.

You don't need to open your bank's website repeatedly. Every time you adjust conditions, results update instantly. You can try "What if the interest rate goes up 1%?" or "What if I shorten the period by 5 years?" as many times as you want, right in your hand.

【Answering Your Concerns with Numbers】
・I want to know if my monthly payment fits comfortably in my household budget
・I want to compare how much the total payment changes between variable and fixed rates
・I want to see how my burden lightens with a down payment or bonus payments
・I want to know how much my repayment amount will increase if interest rates rise
・I want to think ahead to retirement and know at what age I'll finish paying off the loan
・I want to understand how household repayment will work with a pair loan between spouses

【Main Features】

・Real-time monthly payment calculation
Enter the loan amount, interest rate, and repayment period, and instantly calculate your monthly payment, total repayment amount, and total interest. As you adjust the numbers, you'll develop a better sense of the burden.

・Compatible with 3 interest rate types
Switch between and compare variable rate / fixed-period selection type (initial fixed then variable) / full-term fixed rate. With the fixed-period selection type, you can also check how your repayment amount changes when the fixed period ends and switches to the assumed rate.

・Both equal principal-and-interest and equal principal payment methods
Switch with one tap. With the equal principal method, you can see the difference between the first and final payment amounts.

・More detailed variable rate analysis
Set staged interest rates to specify "from which payment the rate changes," or set half-yearly interest rate increase forecasts and calculate. Additionally, switch the repayment review rules "5-year rule" and "125% rule" on and off to compare how much your repayment amount increases when rates rise.

・Bonus payments
Specify the payment month and amount to add to your monthly repayment. You can visualize how lump-sum payments reduce the balance faster and suppress total interest (you can add multiple months).

・Payoff age automatically displayed
Enter your age at the time of borrowing, and the app displays your age at payoff. If you'll be paying off at an advanced age, it alerts you and encourages a more reasonable repayment period.

・Down payment and property price
Automatically calculate the loan amount and self-funded ratio from the property price and down payment. This helps you decide how much down payment to put in.

・Rough estimate of miscellaneous costs
Displays rough estimates of brokerage fees, administrative fees, registration costs, fire insurance, stamp duty, real estate acquisition tax, and more. You can also calculate what happens if you "include it in the loan."

・Pair loan
Calculate combined figures for two people (spouses or dual-income partners). In addition to household monthly payment and total payment, it displays a rough estimate of the ownership ratio based on each person's burden and each person's home loan tax deduction. The full picture of a two-person loan appears clearly on one screen.

・Latest reference interest rates
Obtains and displays representative interest rate levels for variable, 10-year fixed, Flat 35, and other types from the internet. You can reflect them in your calculation with one tap (uses built-in default values if unable to obtain).

・Visualized with graphs
Displays the transition of remaining debt, principal and interest by year, and the ratio of principal to interest in total repayment in intuitive graphs.

・Repayment schedule
Displays the full repayment schedule in a list. You can check the breakdown of principal, interest, and remaining balance for each month in detail.

・Unit conversion tool
Instantly convert between square meters, tsubo, and tatami. Also calculates unit price per tsubo from property price (within settings).

・Scenario save and compare
Save conditions of interest with a name and compare or restore them in a list. You can carefully compare multiple plans and choose the one you're confident about.

【Works Offline Too】
All calculations are completed on your device. Communication is only needed when obtaining the latest reference interest rates. Your input and scenarios are saved only on your device and are not sent to external servers. No tracking or ad display occurs.

【About Usage】
Basic home loan calculations are free to use with no usage limits (monthly payment, total repayment, graphs, repayment schedule, scenario saving, comparison, latest reference rates, etc.). Pair loan combined calculation (household repayment amount, ownership ratio, home loan tax deduction estimate) and miscellaneous cost estimates (calculation) are unlocked with a one-time purchase Pro version (no additional charges after purchase / 300 yen). You can try it free for 7 days before purchase. It is not a subscription.

【Important Notes】
This app is a tool for rough estimation of home loan repayment amounts and does not provide advice on finance, investment, tax, or legal matters. The interest rates, miscellaneous costs, home loan tax deductions, and ownership ratios displayed are all representative reference values and rough estimates; the actual interest rates, costs, borrowing capacity, deduction amounts, and screening results will differ depending on the financial institution and your circumstances. Home loan