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Buying a home is one of the most important financial decisions you will ever make.
It's worth getting right.

Far too many buyers just accept whatever down payment feels comfortable and sign whatever rate their lender offers. But how you allocate your cash at closing has a sizable impact on your family's financial future. Done thoughtfully, it can save hundreds of thousands of dollars in interest, shave many years off the mortgage, or meaningfully increase your family's net worth over time. Most run-of-the-mill mortgage calculators only give you your estimated monthly payment and not a whole lot more. This tool finds the mathematically optimal strategy for your specific numbers and goals.

Every possible down payment tested
Opportunity cost of cash included
PMI tracked to the exact month it ends
Rate buydowns compared dynamically across all loan sizes
Invest vs. pay down modeled with real math based on your specific investment allocations
Absolutely freecost, ever
600+scenarios per run
12kay variables modeled
"The calculator I wished existed when I bought my house."
How it works
Three steps to a smarter mortgage
1
Enter your numbers
Purchase price, closing cash, your lender's rate quotes at each point level, and your monthly budget. Advanced options let you dial in taxes, HOA, maintenance, and appreciation.
2
Pick your goal
Spend the least total? Build the most wealth (even if that means investing instead of paying down)? Own the home free and clear as fast as possible? The optimizer ranks every strategy around what you actually care about most.
3
Get a clear answer
See the recommended strategy with full charts, a year-by-year breakdown, amortization schedule, and a plain-English explanation of why it wins for your specific numbers.
0
What is your main goal?
Pick one. This is how "best" gets defined. You can change it and re-run anytime.
1
Your purchase and budget
The foundation. Everything else is calculated from these numbers.
$
$
Covers down payment + points + closing costs combined
$
Lender fees, title, appraisal, prepaids. Not discount points.
yrs
Until you sell, refinance, or pay off completely
$
$
Scenarios above this payment are filtered out. Your surplus (budget minus required payment) gets optimized separately.
2
What to do with your monthly surplus
The gap between your maximum comfortable payment and the actual required P&I is real money every month. Where it goes changes everything.
Here is the key question: Say your budget ceiling is $2,800/month and the winning strategy only requires $2,100/month. You have $700/month left over. Option A is throwing that $700 at the mortgage every month, paying it off years early and saving a lot in interest. Option B is investing that $700 each month in an index fund at your expected return. This tool runs both calculations and tells you which one actually comes out ahead given your interest rate and investment return.
Applied to every dollar between actual P&I and your budget ceiling
$
Applied to principal at month 1
3
Rate quotes from your lender
Enter every option your lender offered. Point costs are calculated automatically for each down payment scenario, since a smaller loan means cheaper points.
Why point costs are not editable here: One discount point costs 1% of your loan amount. But your loan amount changes with every down payment scenario. A 1-point buydown on a $360K loan costs $3,600. On a $200K loan it costs $2,000. Since the optimizer tests hundreds of down payment levels, it recalculates the actual point cost for each one automatically. You only need to enter the rate your lender quoted at each point level.
Discount points How many points to buy. Zero means no buydown, you take the rate as-is. One point means paying 1% of the loan amount upfront to get the lower rate shown. Interest rate (%) The rate your lender quoted at this point level. Use the exact number from your Loan Estimate document.
4
Where you keep your money
This is the number that makes or breaks the "invest vs. pay down" comparison. Be honest about where your cash actually sits, not where it theoretically could.
Why this matters so much: If the optimizer assumes 7% market returns but you keep everything in a savings account at 4.5%, it will recommend strategies that only make sense for an equity investor. Tell it your real allocation and the recommendation will fit your actual life.
%
S&P 500 long-run real average is about 7%
%
Current HYSA rates run 4 to 5%
%
Federal plus state combined
How do you split your investable cash? Drag or type to set your real asset allocation. The optimizer blends your equity return and savings rate by these percentages to compute a single realistic return assumption. If you keep 100% in a savings account, set equities to 0%. If you go all-in on index funds, set it to 100%.
Equities / market 70%
HYSA / bonds / stable 30%
Blended return used by optimizer
6.25%
70% × 7% + 30% × 4.5%
Advanced options Property tax, HOA, insurance, maintenance, PMI, appreciation, inflation, deductions

Smart defaults are pre-filled for each field below. Updating them with your real numbers will make the results more accurate. Hover the question marks for a plain-English explanation of how each one affects the output.

%
Annual % of home value
$
$
$
Rule of thumb: about 1% of home value per year
%
Annual % of loan. Applies only when down payment is under 20%.
%
%
%
Applied to gains when you exit the investment
Results appear below. No data is stored or shared.
Your results
Your optimal strategy
Recommended strategy
Running...
Why each part of this strategy is set where it is
Down payment
Rate buydown
Monthly surplus
Dig deeper
Total cost over time: Your strategy vs. the extremes
Compares your recommended strategy against the bare minimum (3% down, no points) and overdoing it (maximum possible down payment, maximum available points). The gap tells you exactly how much the optimization is worth.
Net worth at your hold period: Your strategy vs. the extremes
Home equity plus after-tax invested cash. This answers the most important question: does the optimized strategy actually leave you better off than just doing the minimum?
Home equityInvested cash (after tax)
Invest the monthly surplus vs. pay down the loan faster
Recommended strategy, two paths: what total net worth looks like year by year if the monthly surplus goes toward extra principal payments vs. being invested at your blended return. The winner in your situation is the one the optimizer already chose.
Surplus toward principalSurplus invested
Rate buydown break-even by option
Months until each point option pays for itself in lower payments. Rates on the vertical axis, months on the horizontal. Green = recovers before you plan to leave. Red = does not.
Pays off in timeDoes not pay off
Equity you own over time
Recommended strategy only. The portion of the home you own grows from two sources: paying down the loan, and the home gaining value. This chart shows both.
From loan paydownFrom home appreciation
Principal, interest, and PMI year by year
Recommended strategy only. Early payments are mostly interest. Later payments are mostly principal. Extra payments accelerate that shift.
PrincipalInterestPMI
Running interest tab
Recommended strategy only. Total interest paid, growing over time. This is the number a rate buydown reduces the slope of, and the number extra payments cut short.
Year-by-year cash flows: Recommended strategy
Every dollar out of your pocket each year, broken down by category. The highlighted row is your planned exit year.
Amortization schedule: Recommended strategy
First 36 months. The ratio of interest to principal shifts noticeably even within these three years.
What if you stay longer or shorter than planned?
How the recommended strategy's numbers change at different hold periods. Your current plan is highlighted.
What if your investment return is different from your assumption?
Net worth outcomes across a range of market return scenarios. Useful for understanding how sensitive the recommendation is to your blended return assumption.