How Much House Can You Actually Afford?

The rule of thumb that actually has data behind it

Lenders and financial planners converge on the same frame: spend **no more than 28% of gross monthly income** on total housing costs, and **no more than 36%** on all debt combined (housing plus car loans, student loans, credit-card minimums). These are the '28/36' bands — not because they're magic, but because above them, default and distress rates historically climb steeply. Many lenders will *approve* you well beyond 36%; approval measures their risk, not your life.

Work the rule backwards. Household take-home of 5,000 a month: housing budget ≈ 1,400, of which the mortgage principal-and-interest is only one part. That constraint — not the bank's maximum offer — is your real price ceiling.

From monthly budget to maximum price

Turn the budget into a purchase price in three steps. First, subtract non-mortgage housing costs from your 28% allowance: property tax, insurance, and HOA fees commonly eat 20–35% of it. Second, what remains is your maximum principal-and-interest payment. Third, run that payment through the [Mortgage Calculator](/calculators/mortgage.html) in reverse — set the rate and term, and see what loan amount produces your payment — then add your down payment to get the affordable price.

Example: 5,000 take-home, 28% = 1,400. Taxes and insurance estimate 350, leaving 1,050 for P&I. At 6.5% over 30 years, that payment supports roughly a 166,000 loan; with a 40,000 down payment, a ~206,000 home. That's the honest ceiling — before we stress-test it below.

The hidden costs that break budgets

The purchase price is the beginning of the costs, not the end. **Closing costs**: 2–5% of the loan at signing. **Maintenance**: budget 1–2% of home value per year, averaged — roofs, boilers and foundations don't care about your amortisation schedule. **Utilities and commuting**: bigger or farther homes cost more to run every month, permanently. **Furnishing and immediate fixes** reliably surprise first-time buyers by thousands.

Then there's the insidious one: **heating/cooling and taxes rise over time** while a fixed mortgage payment does not — that's a genuine benefit of fixing, but it means the non-mortgage half of your housing cost inflates every year.

Stress-test before you sign

Affordability is not about today's numbers; it's about bad months. Run three checks. **Rate shock**: if you're on any variable structure, or buying where refinancing will happen, compute the payment at +2 points in the [Mortgage Calculator](/calculators/mortgage.html) — could you still pay? **Income shock**: one earner out of work for 4 months — does the emergency fund cover the full housing cost? **Life shock**: child, relocation, major repair — the 36% debt ceiling exists because these arrive eventually for most households.

If the stressed numbers fail, the fix is structural: smaller loan, bigger down payment, or longer runway of savings. Build the down payment with the [Savings Goal Calculator](/calculators/savings.html) — a 20% down payment doesn't just shrink the loan, it usually removes mortgage insurance entirely, a double saving.

When breaking the rule is defensible

Rules of thumb have exceptions. High-income professionals with stable employment and low expenses sometimes sensibly run to 33–35% housing. In some cities, renting equivalent space costs more than owning would — the comparison that matters is ownership cost vs *renting the same life*, not a national percentage. And a rapidly growing income (early career) can justify stretching today for a home you'll grow into. What's never defensible: borrowing the bank's maximum because it was offered, with no stress test and no buffer.

Frequently asked questions

**Do lenders use gross or net income?** Gross — which is why their 'you qualify for X' figure overstates what feels comfortable. **Is 28% before or after tax?** The classic rule uses gross; using take-home is more conservative and more honest. **How big should the emergency fund be with a mortgage?** 3–6 months of *full housing cost* — payment, taxes, insurance, utilities. **What about interest rates when I buy?** Run the numbers at rate, rate +0.5%, and rate +1% before deciding. **Which tool does the math?** The [Mortgage Calculator](/calculators/mortgage.html) for payments, the [Loan / EMI Calculator](/calculators/loan.html) for non-mortgage loans, the [ROI Calculator](/calculators/roi.html) if you're weighing buy-vs-invest.