Quick answer: Start with the monthly payment your household can sustain and the cash you can use without spending your reserve. This mortgage affordability calculator works backward from those two limits to an illustrative fixed-rate loan and home price. It does not estimate what a lender will approve.
Use this if your gross-income borrowing estimate feels disconnected from childcare, debt payments, irregular bills or savings goals. The separate mortgage payment calculator starts with a known home price; this tool starts with your available budget.
Calculate both limits
Illustrative defaults, not live quotes. Enter every field; use zero only when a cost truly does not apply. Do not enter account numbers or personal identifiers.
Select Calculate to see your result.
Prepare the inputs without counting costs twice
The CFPB’s homebuying budget guide separates principal and interest from taxes, insurance and HOA fees, and reminds buyers to allow for utilities, repairs and savings. Use actual local estimates and loan quotes. Costs can change after purchase.
Enter dependable take-home income after payroll deductions. In other living costs, include food, transport, childcare and monthly amounts set aside for irregular non-housing bills. Exclude current rent if the new home replaces it; add any overlap separately to your moving/setup cash. Enter non-housing debt once, in its own field. Do not subtract retirement contributions again if they already reduced take-home pay.
The tax/insurance/HOA field is a monthly dollar total, including mortgage insurance when applicable. Divide annual quotes by 12. The upkeep field includes future utilities and your chosen repair allowance, not the same insurance cost twice. All defaults are fictional; 6.5% is a calculation assumption, not a current market quote.
For cash, separate the reserve you want to keep from closing costs, prepaids and moving costs. Do not put the down payment inside the closing-cost field. The CFPB down-payment guide explains why cash committed to other needs should be removed before deciding what is available.
Worked example: a $1,700 payment limit
| Step | Fictional household calculation |
|---|---|
| Monthly principal-and-interest room | $6,000 take-home − $2,400 living − $400 debt − $600 savings/buffer − $300 upkeep − $600 tax/insurance/HOA = $1,700 |
| Cash available for down payment | $60,000 liquid cash − $20,000 protected reserve − $10,000 closing/prepaids − $5,000 moving = $25,000 |
| 30 years at an assumed 6.5% fixed rate | Loan ceiling about $268,958; add $25,000 down payment for an illustrative $293,958 price |
| Stress check: monthly costs rise $250 | P&I room falls to $1,450; with all other assumptions held fixed, loan ceiling falls to about $229,406 and price to $254,406 |
These figures are a first pass. Property tax, insurance, mortgage insurance and closing costs can depend on the price, location and financing. Re-enter real quotes for the candidate property and calculate again. A result with no down payment is not evidence that a zero-down loan is available to you.
How the math works
Monthly P&I room = take-home income minus the five monthly expense fields. Down-payment cash = liquid cash minus reserve, closing/prepaids and moving. For monthly interest rate r = annual percentage ÷ 1,200 and n = years × 12, loan = P&I × [1 − (1 + r)−n] ÷ r. At 0% interest, loan = P&I × n. Price = loan + down payment.
If monthly P&I room is zero or negative, or protected cash and costs exceed your liquid cash, the calculator shows the shortfall instead of a purchase ceiling. It assumes fixed monthly payments and a fully amortizing loan; it does not model adjustable rates, balloon payments, taxes on income, lender fees financed into the balance or qualification rules.
What to do with the result
Save your assumptions and ask a lender for a property-specific Loan Estimate. Compare the resulting payment with this budget and keep the reserve intact. Once both limits fit, the points versus larger down payment comparison can help evaluate two uses of remaining cash. Do not treat a higher approval amount as a reason to raise your spending limit.
Sources checked November 11, 2026. Dollar Beacon provides general financial education. The calculator runs in your browser without submitting the amounts you enter.