Home Affordability Calculator
Find out how much house you can actually afford — not just what a lender will approve. See the difference between bank maximum and comfortable budget, and what it means for your financial future.
- Gross income vs take-home: Lenders qualify you on gross (pre-tax) income for DTI calculations. The financial flexibility breakdown uses your actual take-home to show what's left after housing and debts.
- Bank Approval Estimate: Uses 43% back-end DTI — the standard conventional loan maximum. Max housing payment = (gross monthly × 0.43) − existing monthly debts. The home price is back-solved from this payment limit.
- Comfortable Estimate: Uses the more restrictive of 28% front-end DTI (housing only) or 36% back-end DTI (housing + all debts). These are the traditional thresholds financial planners use to avoid being house poor.
- Back-solving for home price: Given a max total monthly payment, we iteratively solve for the home price in 3 passes, accounting for the down payment percentage, property tax, insurance, HOA, and PMI. The result is verified by forward-calculating the monthly payment and confirming it matches the target within $1.
- P&I formula: M = P × [r(1+r)^n] / [(1+r)^n − 1], where P = loan amount, r = monthly rate (annual ÷ 12), n = total payments. Identical to the Mortgage Calculator — plugging the comfortable home price into that calculator will produce the same monthly payment.
- PMI: Required when down payment is below 20%. Tiered rate: 0.50%/yr (15–19.99% down), 0.75%/yr (10–14.99%), 1.00%/yr (5–9.99%), 1.25%/yr (below 5%), applied to loan amount. PMI removal date is not modeled here — use the Mortgage Calculator for that.
- FIRE timeline: Estimated using years_to_FI = log(25) / log(1 + savings_rate), where savings_rate = (take-home − housing − debts) / take-home. This is a directional estimate; use RetireSmart for precise modeling with your actual investment plan.
- Privacy: No data is collected or transmitted. All calculations run entirely in your browser.
Frequently Asked Questions
The Bank Approval Estimate uses 43% for both front-end and back-end debt-to-income ratio — roughly the maximum most lenders will approve. The Comfortable Estimate uses a more conservative 28% DTI on both, which leaves room in your budget for saving, investing, and unexpected expenses. The gap between the two is shown explicitly so you can see what "approved" doesn't tell you about what's actually sustainable.
28% on both is stricter than the classic 28/36 guideline's 36% back-end figure — intentionally so, since it leaves more room for savings and investing on top of housing and existing debt, not just enough to avoid being debt-burdened.
Recurring debt obligations excluding your future housing payment — car loans, student loans, minimum credit card payments, personal loans, alimony or child support if applicable. Leave out rent (if you're currently renting) and any housing costs; those are handled separately by the affordability estimate itself.
Lenders calculate debt-to-income ratios using gross (pre-tax) income, so that's what drives both affordability estimates. Take-home pay isn't used in that math — it's used in the "Financial Flexibility" breakdown below, which shows what percentage of your actual take-home pay the comfortable housing payment consumes, since that's the number that reflects your real day-to-day budget.
No — this calculator estimates your ongoing monthly affordability (principal, interest, tax, insurance, PMI, HOA), not one-time costs like closing costs, inspection fees, or moving expenses. Budget separately for those; they typically run 2–5% of the home price on top of your down payment.
It compares your estimated savings rate under the comfortable payment versus the bank-approval payment, using take-home pay minus each scenario's housing cost and existing debts as what's left for savings. The "years closer" figure is a rough approximation of how a higher savings rate compounds toward financial independence — for a precise timeline with your actual investment plan, use RetireSmart.
Mortgage Calculator
Ready to calculate your exact payment? Plug in your home price and see the full amortization schedule.
Rent vs Buy Calculator
Still deciding between renting and buying? See the full picture — break-even year and opportunity cost.
RetireSmart
See exactly how this home fits your retirement and FIRE timeline with your actual investment plan.
How does this home fit your FIRE plan?
This calculator shows how much house keeps you financially flexible. RetireSmart models the full picture — mortgage, savings rate, investment growth, and your retirement date.
Try RetireSmart Free →