Why affordability tools exist
Search interest in “how much house can I afford” is persistent because sticker prices and payments feel disconnected. An affordability sketch translates income and existing debts into a payment budget, then into a loan size and price — with explicit assumptions you control.
Common teaching guidelines mention front-end housing ratios near the high twenties and back-end ratios near the mid-thirties as conversation starters. Products, credit scores, reserves and property types move those lines. The CFPB explains debt-to-income as an underwriting concept, not a consumer entitlement to a specific ratio.
How this calculator works
We take gross monthly income times your chosen DTI percentage as a total debt budget. Subtract other monthly debts and your tax/insurance estimate. What remains is a P&I budget. We invert the mortgage payment formula to estimate a maximum loan, then add your down payment to sketch a price.
If other debts already consume the budget, the tool says so instead of inventing a price. That failure mode is useful: it flags that revolving or installment debts may need attention before a purchase loan is realistic.
Limits and caveats
Gross income is not take-home pay. Student loans on income-driven plans, deferred debts and authorized-user accounts can be treated differently by different investors. Gift funds, seller credits and closing-cost assistance change cash-to-close without changing the payment formula.
HOA dues, ground rents and subordinate financing can affect true affordability. This page does not model residual income tests used in some VA underwriting contexts.
Pair this tool with the mortgage payment calculator once you have a candidate price, and read our guide on rules of thumb.
Next steps
Build a cash-to-close worksheet: down payment, closing costs, prepaid items and a reserve buffer. Compare that cash need with emergency savings so you do not buy a house and become house-poor the same week.
When you speak with lenders, ask them to run scenarios at a few rates and terms. Keep documentation of income and debts consistent with what you typed here so conversations stay grounded.
Privacy and honesty
Calculations run locally in your browser on HomeStack. We do not need an account and we do not receive the numbers you type. Advertisers help keep the tools free; ads are labelled. Affiliate links, when present, use rel="sponsored" and are described in the affiliate disclosure.
Lenders use automated underwriting and overlays this page cannot see. Treat outputs as a budgeting sketch.
Using this tool responsibly means entering figures from your statements or quotes, changing one input at a time, and treating the output as a conversation starter with a licensed professional — not a decision by itself.