HouseMath
Mortgage, rent, buy calculator
Only for iPhone
Free · Designed for iPhone. Not verified for macOS.
iPhone
HouseMath answers the three questions that actually matter when you are buying a home: what will it cost me every month, how much house can I afford, and am I better off buying at all?
THREE CALCULATORS
Mortgage works out the real monthly cost of a specific house. Principal and interest is only part of it. The property tax, home insurance, mortgage insurance and HOA dues are what turn a cheap-looking loan into a real payment.
Affordability works the other way round. Enter your income, your existing debts and the cash you have for a down payment, and it solves for the most expensive house that still fits inside a lender's debt-to-income limit. It shows its working, so you can see how your income caps the loan and the down payment sits on top.
Growth compares what your cash could become. Buy a home to live in, or rent and put the difference into stocks or gold, and see where each leaves you in five to thirty years. You can model a refinance too.
THE WHOLE PAYMENT
Principal and interest, property tax, home insurance, PMI and HOA broken out separately, with a bar showing the real proportions at a glance.
REAL AMORTIZATION
A complete schedule, by year or by month, with principal, interest and remaining balance for every payment. Charts show the crossover where you finally start paying down more principal than interest, and what the loan costs in total.
LOCAL ESTIMATES FROM YOUR ZIP
Property tax, home insurance and home price growth are all estimated for your state. Tax is the rate a new buyer actually pays on the purchase price, not the published average that assessment caps distort. Insurance is priced off rebuild cost, because policies cover the structure and not the land. Mortgage tax and insurance estimates can be overridden; Growth tax and home-price growth are editable.
PMI HANDLED PROPERLY
Below 20% down, mortgage insurance is added automatically at a rate based on your loan-to-value, and switches off again the moment you cross 20%. Or take manual control and set it yourself. The schedule shows the month it drops off at 78% LTV.
BUILT ON REAL DATA
Growth projections use thirty years of market history: FHFA state house price indices, S&P 500 returns, Treasury yields, World Bank gold prices and CPI. Every rate is shown and every one can be edited.
CURRENT RATES
Opens with a recent Freddie Mac survey rate and refreshes in the background, so it is current when you have signal and still works when you do not.
PRIVATE BY DEFAULT
No account, no sign-up, no analytics, no tracking, no ads. Your figures stay on your device and are never sent anywhere.
ABOUT THE ESTIMATES
Tax and insurance figures are statewide approximations held flat over the life of the loan, and your lender's numbers will differ. The affordability result is a debt-to-income guideline, not a pre-approval. Growth projections apply historical averages evenly forward; markets do not move in straight lines, so they are a projection rather than a prediction. HouseMath is an estimating tool and does not give financial advice.
New feature:
Allows to save a one page PDF summary of any mortgage calculation, suitable printing and ready to email.
Bug fix:
1. Fixed: a pasted amount like $800,000.00 could be read as eighty million. Rates and amounts typed in locales that group with periods are read correctly.
2. Fixed: sliders could stop following your finger until you lifted off and tried again.
3. The app now keeps the last mortgage rate it fetched, so it no longer falls back to the default rate it shipped with when it cannot reach the rate service.
The developer, Gray Glen, LLC, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Gray Glen LLC
- Size
- 1.6 MB
- Category
- Finance
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - Mac
Requires macOS 14.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- Copyright
- © 2026 Gray Glen LLC