HOW ESTIMATES WORK
Useful numbers.
Not pretend precision.
Buy or Bolt is an educational planning tool, not financial, lending, insurance, tax, or investment advice. A BUY, THINK, or BOLT result is not a recommendation to purchase or avoid a property.
Quick-mode assumptions
- 30-year fixed loan using the current Freddie Mac PMMS weekly national average, loaded when the calculator opens and clearly editable. The live result is cached for reliability; if Freddie Mac is temporarily unavailable, the calculator labels and uses its last verified value. Your actual rate may differ.
- Property taxes use the 2024 Census ACS ZIP Code Tabulation Area median real-estate-tax and median-home-value data, scaled to the entered price. This is a ZIP-area fallback, not a parcel tax bill; use a listing or assessor amount whenever available.
- Home insurance uses a state-average annual premium selected from the ZIP code. It is a planning baseline, not a quote, coverage limit, or availability check. California, Florida, and Louisiana require a property-specific quote.
- Upkeep reserve defaults to 0.50% of the home price per year. A 1.00% conservative option is available for homes with more repair risk.
- PMI is estimated from down-payment percentage when the down payment is below 20%.
How the verdict works
- BUY means the estimate preserves the full monthly savings goal and keeps 5% of take-home pay unassigned as monthly breathing room.
- THINK means the payment is possible without a monthly shortfall, but it reduces the savings goal or uses that breathing room.
- BOLT means the estimate creates a monthly shortfall or leaves less than half of the stated savings goal.
The comfortable target follows the BUY rules. The stretch ceiling follows the boundary between THINK and BOLT, so the result card and price ladder use the same rules. Both targets hold the entered down-payment dollars constant; choosing a higher target never assumes the user has additional cash available.
Lender Lens
Lender Lens follows the CFPB definition of DTI: the proposed housing payment plus entered recurring debts, divided by entered gross monthly income. It excludes the upkeep reserve. The ranges reflect common conventional review points described in the Fannie Mae Selling Guide, but they are educational references—not approval odds or a preapproval.
Future Fit
Future Fit compounds the entered balance and end-of-month contributions monthly using a 7% nominal annual return. Results are future-dollar illustrations before inflation, taxes, and fees. Returns are not guaranteed.
What to verify
Before making any housing decision, verify the actual rate, tax bill, insurance quote, HOA dues, flood coverage, utilities, closing costs, repair needs, and loan terms. Assessment and insurance costs can vary dramatically, including within the same ZIP code.
Data source
ZIP tax profiles are bundled in the site from U.S. Census Bureau, 2024 American Community Survey 5-Year Estimates, tables B25103 and B25077. State insurance baselines are 2025 averages for a sample $300,000 dwelling policy from Bankrate’s analysis of Quadrant Information Services rates. The Census data covers 2020–2024 and uses ZCTAs, which are approximations of postal ZIP service areas.