Most people approach home buying backwards: they look at houses they like, then discover they can’t afford them. This creates anchoring bias — everything under budget feels like a compromise. Use our home affordability calculator first, set a firm number, then look only at homes within that range.
What Mortgage Lenders Will Approve vs What You Should Spend
These are two very different numbers. Lenders approve up to 43-50% DTI — meaning you can spend nearly half your income on debt. Financial advisors recommend 28-36% DTI. The gap between lender maximum and comfortable maximum is where many buyers become house poor.
How to Use the Home Affordability Calculator Correctly
The calculator asks for gross income, down payment, debts, and expected rate. Here are the critical inputs to get right:
Use Take-Home Pay for Comfort Testing
Gross income is what lenders use. But your mortgage payment comes from take-home pay. Run the calculator with gross income for the lender standard comparison, then check: does the resulting payment feel comfortable against your actual take-home income?
Include All True Monthly Debts
Don’t forget: car payment, student loans, credit card minimums, personal loans. Every monthly obligation reduces your approved mortgage amount and your comfort level. Use our DTI calculator to see the full picture.
Account for All Housing Costs
The mortgage payment is just one piece of homeownership cost:
| Cost | Typical Range | Monthly on $350k Home |
|---|---|---|
| Mortgage P+I | – | ~$2,100 |
| Property tax (1.2%/yr) | varies by state | ~$350 |
| Homeowners insurance | 0.5-1.5%/yr | ~$175 |
| PMI (if under 20% down) | 0.5-1.5%/yr | ~$175 |
| HOA (if applicable) | $0-600+ | varies |
| Maintenance reserve | 1-2%/yr | ~$290 |
| Total Monthly Cost | ~$3,090+ |
The 3 Affordability Rules Worth Knowing
- 28% rule: Total housing costs under 28% of gross monthly income
- 3× rule: Home price under 3× annual gross income (conservative)
- 20× rule: Down payment should be at least 5% of purchase price (realistic floor)
Improve Credit Before Your Mortgage Application
Every 20-point credit score improvement can reduce your mortgage rate by 0.25-0.5% — worth tens of thousands over the loan life. Our dispute letter bundle helps clean your report before you apply.
20% avoids PMI and gives the best rates. 10% is a reasonable middle ground. 3-5% FHA allows entry with limited savings. Whatever you put down, keep 3-6 months of mortgage payments in reserve for emergencies — don’t drain savings completely for a down payment.
Get pre-approved from 1-3 lenders before looking at homes. Pre-approval takes 1-3 days per lender, shows sellers you’re serious, and confirms your actual borrowing capacity. Rate shopping multiple lenders within 45 days counts as one hard inquiry for FICO scoring.
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