Purchase Power Calc

It shows how big a mortgage your target monthly payment can support at nine different interest rates — a 9×9 grid of monthly principal-and-interest payments across a range of loan amounts and rates, so you can see exactly where your payment lands.

You give it two things: a max purchase price and a target monthly payment. The tool then builds a table. Down the side are nine interest rates, from 7.5% down to 3.5% in half-point steps. Across the top are nine loan amounts, starting at your max price and stepping down in $25,000 decrements. Every cell is the 30-year monthly payment for that rate-and-loan combination, and any cell at or below your target payment is highlighted green.

The point is to answer one question fast: "At today's rates, what size loan keeps me at the payment I want?" It is a rate-versus-loan-size map, not an application.

Each row is an interest rate, each column is a loan amount, and each cell is the 30-year monthly principal-and-interest payment — green cells are the combinations that fit your target payment.

• Rows (rates) — run top to bottom from 7.5% to 3.5%. Lower rows are lower rates.
• Columns (loan amounts) — start at your max purchase price and step down $25,000 at a time.
• Cells (payments) — the monthly P&I for that rate and loan, rounded to whole dollars.
• Green cells — the payment is at or below your target. These are the affordable combinations.

If an entire row is green, your target payment covers your full max price at that rate. If a row has no green, that rate is too high for the price and payment you entered — you would need a lower rate, a smaller loan, or a higher payment.

The purchase price is what the home costs; the loan amount is what you borrow after your down payment — this grid works in loan amounts, because that is what determines the payment.

If you buy a $500,000 home and put $50,000 down, your loan amount is $450,000, and the payment is calculated on that $450,000 — not the full price. This calculator's grid columns are loan amounts stepping down from the max price you enter, so the cleanest way to use it is to enter the loan figure you are actually financing.

Rate is the single biggest lever in this grid: on a 30-year loan, every 1% change in rate moves your payment by roughly $66 per $100,000 borrowed — so a lower rate lets the same payment carry a bigger loan.

Worked example on a $400,000 loan, 30-year term:

Read the right column: at a $2,500 target payment, dropping from 7.5% to 5.5% — two points — lifts the loan you can carry from about $357,500 to $440,300, roughly $83,000 more house for the exact same monthly payment. That is why locking a good rate matters more than almost any other number on the page.

Because a higher rate means more of every payment goes to interest instead of paying down the balance — so to keep the payment fixed, the loan amount has to shrink.

Your monthly payment is split between interest (the cost of borrowing) and principal (paying back the loan). When the rate goes up, the interest slice of a fixed payment grows, leaving room for a smaller loan. Hold the payment steady at $2,500 and the math is unforgiving:

Each full point higher costs this buyer roughly $40,000–$45,000 of loan capacity. It is not the home that changed — it is how far your payment stretches. This is exactly the dynamic the grid is built to make visible.

No — this is a payment-and-rate map, not an affordability or pre-approval tool. It shows P&I only and never looks at your income, debts, or debt-to-income (DTI) ratio.

Real qualification depends on numbers this calculator never asks for:

• Income and debts — lenders approve you on your debt-to-income ratio, not just a payment you pick.
• Down payment — this grid works in loan amounts and does not model your down payment.
• Taxes, insurance, and mortgage insurance — none of these are in the grid (see below).

Use this tool to understand how rate moves the loan size your target payment supports. To find what you can actually qualify for, run our What Can I Afford calculator, which factors in income and DTI, and then get a real pre-approval with us.

No — every cell in the grid is principal and interest (P&I) only, with nothing added for taxes, insurance, or mortgage insurance.

Your real monthly housing payment also includes property taxes, homeowners insurance, and — if you put less than 20% down — mortgage insurance (PMI or MIP). Together those can add a few hundred dollars a month, so your true payment will sit above the P&I numbers shown here.

This tool leaves them out on purpose: P&I is the part that rate and loan size directly control, which keeps the rate comparison clean. For a full PITI payment that includes taxes and insurance, use our What Can I Afford calculator.

Every payment in the grid assumes a fixed 30-year loan term, and the rows cover nine rates from 7.5% down to 3.5% in half-point steps.

The rate range is wide on purpose. Some of those rates may be well above or below today's market, but seeing the full ladder shows you how much buying power swings as rates move — useful whether you are shopping now or watching for a chance to refinance later. The numbers are estimates; your actual rate depends on credit, loan type, points, and the market on lock day.

Enter your max purchase price and your target monthly payment — the grid fills in instantly and highlights every rate-and-loan combination that fits.

• Type your max purchase price (or the loan amount you would finance) — the columns step down from here in $25,000 increments.
• Type your target monthly payment — the most P&I you want to pay each month.
• Read the grid: green cells are at or below your target. Find your quoted rate's row, then read across to the largest green loan amount.

The takeaway is the loan size your payment supports at each rate. When you have a number you like, bring it to us — we will pressure-test it against your actual income and DTI and turn it into a real pre-approval.

An all-green row means your target payment comfortably covers your full max price at that rate; a row with no green means that rate is too high for the price and payment you entered.

• All green — even the largest loan in that row costs less than your target payment. You have room to buy more, lower your payment, or keep the cushion.
• Some green — the typical case. The first green cell from the right marks the largest loan that fits at that rate.
• No green — at that rate, every loan in the row exceeds your target. You would need a lower rate, a smaller loan amount, or a higher target payment.

If higher rates show no green but lower rates do, that is your signal that buying power at your target payment is rate-sensitive — and that a temporary or permanent rate buydown could be worth pricing. See our Temporary Buydown calculator to explore lowering the rate for your first few years.