How Much House Can I Afford? A Budget Guide

Asking “how much house can I afford” sounds like a single question, but it hides two very different ones: what payment can you make reliably every month, and what purchase price that payment can support at today’s rates. Lenders answer the first question for themselves during underwriting. You should answer both before you start touring homes. This guide walks through the math lenders use, the costs shoppers most often leave out, and how today’s advertised rates shape the answer. It is general education — it cannot replace a lender’s actual underwriting or a financial professional’s advice.

Start with the payment, not the price

A home’s price is only the entry ticket. The durable cost is the monthly housing payment, and everything lenders verify — income, debts, assets, credit history — is aimed at judging whether that payment is sustainable. When shoppers fixate on the price first, they sometimes pick a number, fall in love with houses at that number, and discover only later that the payment demands more than their budget can carry.

Invert it: size the monthly payment you can carry with room to spare, and then let the price follow from the rate, the down payment, and the rest of the costs on the page. The sections below walk that sequence in the same order a lender’s math works.

Debt-to-income ratio: the measure lenders compare

The centerpiece of affordability math is the debt-to-income ratio, or DTI. In its simplest form, it divides your monthly debt payments by your gross monthly income — the income before taxes and deductions. Lenders apply versions of it to every application, with tolerances set by each loan program.

Two ratios, not one

Mortgage underwriting looks at two versions of the same relationship. The housing ratio, sometimes called the front-end ratio, compares the full monthly housing payment — more on its parts in a moment — against gross income. The total-debt ratio, or back-end ratio, compares all recurring monthly debts against that same income. A borrower passes only when both ratios fit inside the program’s ceilings.

Those recurring debts typically include minimum credit card payments, auto loan and student loan payments, child support or alimony obligations, and the proposed housing payment itself. Lenders generally count the debts that appear on the credit file plus documented obligations such as taxes owed under payment plans; they do not typically count utilities, groceries, subscriptions, or presumed savings targets. The math therefore ignores several things that genuinely compete for your dollars — one reason the approved maximum and the comfortable maximum usually differ.

The 28/36 guideline — and where it bends

A commonly cited rule of thumb holds that the housing payment should consume no more than 28 percent of gross monthly income, and that all debts combined should consume no more than 36 percent. Treat this as a starting point, not a rule. Individual loan programs publish their own ceilings — some more forgiving, particularly with strong credit histories and reserves — and compensating factors such as large cash reserves or a long employment history can matter to underwriting.

Note also that the guideline assumes steady income. Commission-based pay, self-employment income, bonuses, and recent job changes are scrutinized and typically averaged over several years under program rules, and the income a lender recognizes may differ from the income you planned around. Always use the income the lender will recognize, not simply the deposit that hit your account last month.

What counts as the housing payment

Underwriting does not stop at principal and interest. The payment a lender evaluates — and the payment you will actually make — includes every recurring cost attached to living in the home. A payment-only estimate that forgets the rest overstates how far the budget reaches.

Principal, interest, taxes, insurance: PITI

The foundation is PITI: principal and interest on the loan, property taxes paid to the local government, and homeowners insurance premiums paid to the insurer. Many lenders collect the tax and insurance portions monthly into an escrow account and pay the bills for you, which spreads large annual amounts into predictable installments — the same escrow mechanic our Learn lessons describe.

Escrow makes budgeting easier, but it does not fix the total. Tax reassessments and premium renewals can move the payment in either direction at any time, even when the mortgage itself carries a fixed rate. Treat principal and interest as the stable core of the payment, and taxes and insurance as the parts that revisit you annually.

The add-ons people forget

• Private mortgage insurance (PMI): conventional loans with smaller down payments often add a monthly PMI premium. It protects the lender, not the borrower.
• HOA, condo, and co-op charges: mandatory dues that lenders count against the housing payment.
• Flood, wind, or earthquake riders where required: extra premiums on top of standard homeowners insurance in exposed areas.
• Special assessments: condo and HOA capital projects can layer large temporary payments onto regular dues.
• Local special levies: improvement-district and municipal charges that behave like extra property tax.

Any of these can add hundreds of dollars to the monthly total. Because the affordability formula compares the full payment against income, forgetting an add-on inflates the price the math appears to support — and the surprise arrives after the offer is accepted, which is the worst time to meet it.

The down payment’s role

The down payment does three things at once: it shrinks the loan amount directly, it lowers the loan-to-value ratio the lender prices against, and it leaves financial slack that lenders otherwise look for in bank reserves. Each effect pushes the affordability number in the same direction, but the third one is the one cash-strapped buyers notice least.

A smaller loan means a smaller principal-and-interest base for everything else to build on. The loan-to-value ratio — the loan compared with the home’s value — can also influence pricing: higher ratios can mean less favorable rates or stricter program limits, and a conventional loan with a smaller down payment often needs private mortgage insurance until enough equity has been built. Ask any lender how much PMI costs, when it may be removed, and whether a higher rate is being offered instead of PMI so you can compare the whole deal.

Even so, do not stretch the down payment until closing costs, moving expenses, and emergency reserves fall away. The payment your income supports assumes you can keep making it through an unexpected expense — a budget with no slack cannot keep that promise, no matter what the ratios allow.

Where today’s advertised rates enter the math

The interest rate is what converts the payment into a price — and advertised rates vary widely across lenders with different published assumptions. In LoanMate’s September 30, 2026 snapshot, the 200 verified 30-year fixed purchase observations carried advertised rates from 5.50% to 8.425%, averaging about 6.75%. Each figure reflects the credit, down-payment, and points assumptions that lender published, which differ from row to row, so the range shows the market’s spread rather than a price anyone could pick freely.

What the range does to buying power

To isolate the rate’s pull, hold a single payment steady and move the rate through that advertised range. At $2,800 a month devoted to principal and interest:

• At 6.75%, near the observed average, the payment supports a loan of about $432,000.
• At 5.50%, the lowest advertised observation, it supports about $493,000.
• At 8.425%, the highest advertised observation, it supports about $367,000.

The same payment spans roughly $126,000 of borrowing power between the advertised floor and the ceiling — before taxes, insurance, PMI, and other housing costs take their share. This illustration deliberately shows principal and interest only; the real version of your budget includes all of the add-ons earlier in this guide, and the advertised floor and ceiling come from rows with different lender assumptions. Compare the actual figures in the purchase mortgage rate tables — each row carries its own last-verified date and a link to the lender’s own page — and confirm the rate each lender would actually hold.

An example, start to finish

Take a household with $120,000 of gross annual income — $10,000 a month — and $1,200 of non-housing monthly debts: an auto payment, student loans, and minimum credit card payments. The 28% housing guideline suggests a full housing payment target of about $2,800; the 36% total-debt guideline targets about $3,600 across all obligations, which leaves housing room of about $2,400 after the $1,200 of existing debts. The tighter of the two — $2,400 — governs, and that figure must cover principal, interest, taxes, insurance, PMI, and any dues.

At 6.75% on a 30-year term, $2,400 of principal and interest supports a loan of about $370,000. A 20% down payment layered on top would support a home price of about $462,500 — again before the tax, insurance, and HOA shares come out of the housing target. Move to the snapshot’s advertised floor of 5.50% and the same $2,400 supports about $423,000; move to the ceiling of 8.425% and the number falls to about $314,000.

Fixed versus adjustable in the affordability math

Adjustable-rate mortgages can advertise lower opening rates than comparable fixed loans, which flatters the affordability math on day one. An adjustable-rate mortgage starts fixed for a set period, then can change on a schedule using an index, a margin, and adjustment caps. What matters for your budget is not only the opening payment but where it could land after the scheduled adjustments, read the same way the lender discloses it. Underwriting typically tests against that adjusted payment rather than the teaser.

Credit and the specific rate you can hold

Lenders publish advertised figures under stated credit assumptions, and the same lender’s pages often carry multiple columns for different profile bands. The number that should travel through your affordability math is not the lowest row you can find — it is the row whose credit, down-payment, term, and points assumptions resemble your own profile. The snapshot’s 5.50%-to-8.425% spread comes from many different assumption sets, so two borrowers can read two completely different prices out of the same market.

Ask each lender which assumption set applies to you, get the answer in writing, and rerun the math if the answer differs from the published baseline. The advertised tables are a way to compare lenders’ pricing discipline and coverage, not a pre-approval.

Your budget is the binding constraint

Receiving approval for a mortgage is not the same as being able to afford it. The underwriting ratios intentionally exclude some of life’s largest planned spending — retirement savings, future tuition, the car-replacement cycle — and they assume the income behind them arrives steadily. Your own budget knows about all of those things, plus the irregular costs of the house itself, which arrive in lumps: roofs, furnaces, water heaters, and the maintenance calendar that never quite empties.

Before committing to a price band, run the full housing payment against next year’s actual spending plan rather than the lender’s ratios alone. A practical discipline is to simulate the future payment for a few months: route the difference between today’s housing cost and the projected payment into savings, and see whether life still works. If it strains, the price band is too high, no matter what the ratios allow. And remember the payment can drift after closing — property-tax reassessments and insurance renewals do not ask permission.

Put the numbers together

Work the sequence in the order the math is built: gross monthly income, recurring debts, the commonly cited ratios as a plausibility check, the full housing payment with every add-on you can estimate, and finally the range of rates lenders are actually advertising. Our free loan calculators — DTI, affordability, and monthly payment — run that chain on numbers you enter, and nothing you type is saved.

Then test the rate side against the market itself: the purchase mortgage rate tables compare advertised purchase rates with each row’s points, APR, assumptions, and verification date, while the refinance rate tables separate genuine refinance pricing from purchase-table assumptions. All advertised figures are the lenders’ own information from the verification date — confirm the current terms directly with each lender before applying.

Keep reading in the Learn center. Our guide Mortgage points vs rate: are points worth it? explains how paying upfront for a lower rate shifts the payment you budgeted against, and HELOC vs home equity loan: which one fits? covers the equity-borrowing comparison that arrives once you own. Shorter term-by-term explanations stay in the Learn library above.