Income + debt + down payment + rate → the max home price a lender's 28/36 rule will actually approve — browser-only
- Runs locally
- Category Calculator
- Best for Getting a realistic range before a purchase, plan, workout, or schedule decision.
Car, student loans, minimum credit-card payments — not rent/mortgage.
Property tax, homeowners insurance, HOA dues — they share the housing cap.
What this tool does
Lenders don't ask how much you want to spend — they ask how much your debt-to-income ratios let you borrow. This calculator runs the same 28/36 underwriting rule conforming mortgages use: monthly housing payment under 28% of gross monthly income (front-end), housing plus every other debt under 36% (back-end). Enter gross annual income, recurring monthly debt (car, student loans, card minimums), down payment, rate, and term. The tool finds the binding cap, subtracts taxes/insurance/HOA, inverts the amortization formula for the largest loan you'd qualify for, then adds your down payment for the maximum home price. It also reports the monthly P&I, total housing cost, and payment-to-income ratio, so you see which rule limits you. Both caps are editable for FHA (31/43) scenarios.
Tool details
- Input
- Numbers
- The page exposes text boxes, numeric controls, file pickers, or structured inputs depending on the tool.
- Output
- Live result + Copy
- The result area focuses on usable output, with copy, download, or preview actions when supported.
- Privacy
- Browser-side processing
- The main tool logic does not call an external API, so inputs normally stay in the current tab.
- Save / share
- Shareable URL state
- Key settings are encoded in the URL so another person can reopen the same setup.
- Performance budget
- Initial JS <= 9 KB
- No WASM budget is declared, keeping the tool quick to open on mobile.
- Best fit
- Calculator · Finance
- Category and role tags drive related tools, internal links, and quick fit checks.
How to use
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1. Input
Paste or drop your content into the tool panel.
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2. Process
Click the button. All processing is local in your browser.
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3. Copy / Download
Copy the result or download to disk in one click.
How Home Affordability Calculator fits into your work
Use it for fast estimates, comparisons, and planning numbers before you make the final call.
Calculation jobs
- Getting a realistic range before a purchase, plan, workout, or schedule decision.
- Comparing scenarios by changing one input at a time.
- Turning rough assumptions into a number you can discuss.
Calculation checks
- Double-check units, dates, rates, and rounding assumptions.
- Treat health, finance, tax, and legal outputs as planning aids, not professional advice.
- Save the inputs that produced an important result so you can reproduce it later.
Good next steps
These links move the current task into a more complete workflow.
- 1 Mortgage Calculator Mortgage calculator — monthly payment, total interest, amortization schedule, early payoff scenarios. Open
- 2 Rent vs Buy Calculator See whether buying beats renting and investing the difference — net cost, terminal equity, and the break-even year, all in your browser Open
- 3 Loan Comparison Calculator Loan comparison calculator — compare equal-payment vs equal-principal, multiple loans side by side, total interest breakdown. Open
Real-world use cases
Set a realistic budget before you open a listings app
Most house-hunting starts backwards: you fall in love with a $650k listing, then find out the bank caps you at $480k. Run this first. Punch in your $120k salary, $400/month car payment, and $60k saved — you'll see the 28% rule lands you around a $530k price with 6.5% rates. Now you browse the right tier of listings instead of touring homes you can't finance, and you walk into a lender meeting already knowing the number they'll quote.
See whether paying off the car first unlocks a bigger house
You have a $550/month car loan and you're $40k short of the home you want. Toggle the monthly-debt field to $0 and watch the max price jump — that's the back-end (36%) cap loosening. If the jump is bigger than $40k, paying off or refinancing the car before you apply is the cheapest way to qualify for the house, and it costs nothing in rate or down payment.
Compare an FHA 31/43 scenario against a conventional 28/36
FHA loans let your ratios run higher — 31% front-end, 43% back-end — which can mean tens of thousands more in buying power if you're debt-light but income-constrained. Set the caps to 31 and 43, note the new max price, then flip back to 28/36. The gap is exactly how much extra house the FHA underwriting buys you, before you weigh the mortgage-insurance cost against it.
Stress-test affordability at next year's rate
Rates moved from 6% to 7.5% and you want to know what that does to your ceiling before locking. Keep every other input fixed and change only the rate. A point and a half typically shaves 12-15% off the max loan, because the inverse amortization is rate-driven. Seeing the dollar figure — not just "rates went up" — tells you whether to lock now or wait, and by how much your offer must drop.
Right-size your down-payment savings goal
You want a $500k home and you're deciding between saving $50k or $100k. Enter each down payment and read the down-payment-percent readout: $50k on a $500k price is 10% (PMI territory), $100k is 20% (PMI drops). Because the loan ceiling is income-driven, the extra $50k goes straight onto price AND tips you past the PMI threshold — the tool shows both effects at once.
Common pitfalls
Counting rent as debt. Your current rent does NOT go in the monthly-debt field — it disappears once you buy. Only put obligations that survive the purchase (car, student loans, card minimums). Including rent understates your affordability by a lot.
Forgetting taxes and insurance. A "$2,800/month I can afford" budget is the full housing cap, not the loan payment. Property tax + insurance + HOA can be $400-700/month and they come out of that same 28% — leave the extras field at zero and you'll overestimate the home price you qualify for.
Treating the down payment as borrowing power. A bigger down payment adds to the price dollar-for-dollar, but it does NOT raise the loan the bank will approve — that ceiling is set entirely by your income and the two DTI caps. Don't assume "save more = qualify for more loan."
Privacy
Every number you enter — income, debt, down payment, rate — is processed by plain JavaScript inside your browser tab. Nothing is uploaded, logged, or sent to any server; there is no backend that ever sees your salary. The one caveat: the shareable URL encodes your inputs in the query string so a "share scenario" link reproduces the same result. That means your income and debt figures sit in the link. For a quick scenario that's fine, but if you'd rather not have your salary in a URL pasted into a chat or email, use the Copy-result button instead of the share link.
FAQ
Tool combos
Folks in your role tend to reach for these alongside this tool.
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