Home & property · 2 min
Affordability calculators are built by lenders, so they answer a lender's question: how much will the bank extend. This instrument answers yours: the price at which the full monthly carry — payment, tax, insurance, upkeep — stays under the 28% line read against net income, and still stands when rates move two points against you.
The ownership bill beyond the bank.
The affordability that matters is at renewal, not at signing.
Everything is calculated in your browser as you type. Nothing you enter is sent or stored, and no account is needed.
Stress decides the price — as it should.
$613,000
the price the 28% line affords, stress included
| Monthly budget at the 28% line | — |
| The price that budget carries today | — |
| The price it carries at the stressed rate | — |
| Loan at that price, after your down payment | — |
| Monthly carry at the affordable price | — |
| If the rate is | Affordable price | Monthly carry |
|---|---|---|
| — | — | — |
| — | — | — |
| — | — | — |
Lender pre-approvals routinely exceed this figure, because the bank prices default risk, not your life. The gap between their number and this one is the room your life was going to live in.
The 28% line assumes the rest of the balance sheet is normal. Heavy other debts, thin emergency funds or variable income all argue for reading the line lower, not higher.
Buying at the top of affordability converts every future rate move into a household event. The stress row is the page's most important line — believe it before the headline figure.
Everything below is calculated from your inputs. Nothing is fetched, nothing is looked up.
budget = 0.28 × net_monthly
price solves: pmt(price − down, rate, term) + price × carry/12 = budget
stress = same, at rate + stress_points → the binding figure
The gauge reads the affordable price's monthly carry against net income, the line at 28% — the classic front-end ratio, deliberately read against net rather than the lender's gross. The binding answer is the stressed one: a house afforded only at today's rate is rented from the central bank.
Limitations. Closing costs, moving, furniture and the first-year surprises sit outside the ratio; so do local property-tax regimes that differ from the flat carry percentage. The 28% line is a convention — the point of naming it is that you can move it.