Estimate the maximum mortgage and home price a lender would likely preapprove you for, using the front-end and back-end DTI rules they actually apply.
This is an estimate for planning, not a preapproval. A lender verifies income, credit, assets, and the property before issuing a real preapproval letter.
Lenders rarely approve you for a round number pulled from your salary. They work backward from two debt-to-income (DTI) ratios and approve the smaller of the two results.
The calculator computes the housing budget each rule allows, then uses the lower one. That's the "binding" limit you'll see flagged in your results.
Your housing budget has to cover more than the loan. The calculator subtracts estimated property tax, insurance, PMI (only if your down payment is under 20%), and any HOA before working out how much is left for principal and interest.
The leftover principal-and-interest budget is run through the standard mortgage formula in reverse to find the largest loan it can support:
Loan = M × (1 − (1 + r)−n) / r
where M is the monthly principal-and-interest budget, r is the monthly interest rate, and n is the number of monthly payments. Because tax scales with the home's value and PMI scales with the loan amount, the calculator solves these together so the final number stays internally consistent. Your maximum home price is simply the loan plus your down payment.
A preapproval is a lender's written estimate of how much they're willing to lend you after a first-pass review of your income, debts, credit, and assets. It's stronger than a prequalification — which is usually just a conversation — because the lender has looked at documentation and pulled your credit. Sellers take preapproved buyers more seriously, and it tells you the price range to shop in before you fall for a house you can't finance.
What it is not: a guarantee. The number on a preapproval letter is a ceiling based on the snapshot you gave. The final loan still depends on the specific property's appraisal and a re-check of your finances right before closing.
Once you submit documents, a preapproval can come back the same day to a few business days, depending on the lender and how complete your paperwork is. Most preapproval letters are valid for 60 to 90 days, because your credit and finances can shift over time. If you're still shopping after it expires, the lender refreshes it with updated information.
The fastest ways to undo a preapproval are taking on new debt (financing a car, opening a credit card), making large unexplained deposits, changing or quitting your job, or letting a payment go late. Each of these changes the financial picture the lender approved. The safest move during the window is to keep your income, debts, and accounts as stable as possible until you close.
Preapproval reviews you; final approval also reviews the property and re-checks your finances. A low appraisal, a title issue, a change in your debts, or a fresh credit pull that reveals new accounts can all move the final number — or stall it. Treating the preapproval amount as a firm budget rather than a target to max out leaves you room if something shifts.
No. It runs entirely in your browser using the numbers you enter, makes no credit inquiry, and produces an estimate only. A genuine preapproval requires applying with a lender who verifies your information.
Not necessarily. The preapproval ceiling is what a lender will allow, not what's comfortable. The 28% front-end figure is the more conservative guide; many buyers deliberately shop below their maximum to leave margin for maintenance, savings, and rate or tax changes.