Calculator Methodology

Formula Principles

We use standard formulas where the domain has a widely accepted calculation. Mortgage and loan tools use amortization math. Rental and investment tools use explicit income, expense, debt-service, cash-flow, and return formulas. Date tools use calendar arithmetic with leap-year handling.

When a calculation depends on a local market assumption, we separate the formula from the assumption. That lets the same formula run across different states while keeping the state-specific values visible and auditable.

Real Estate Assumption Hierarchy

For state-specific real estate data, our preferred source order is:

1. Official government, statute, regulator, or tax authority.
2. Primary market data publisher for market measures.
3. Professional industry source when official data is unavailable.
4. Documented calculator default with a clear limitation note.

The current state-property-tax baseline uses Tax Foundation Table 2, which reports 2024 property taxes paid as a percentage of owner-occupied housing value. Transfer-tax, title, attorney, and proration assumptions are documented separately because legal liability and customary closing practice are not always the same thing.

Insurance Estimates

Homeowners insurance is not modeled as a straight-line price multiple. The app interpolates between national dwelling-coverage premium breakpoints, then applies a state multiplier. That means a $200,000 property is not assumed to cost exactly twice as much to insure as a $100,000 property.

Insurance markets change quickly in states exposed to hurricanes, wildfire, hail, and carrier exits. Florida, California, Hawaii, Louisiana, Texas, Oklahoma, and Nebraska deserve more frequent review than lower-volatility states.

Stress Testing

The real estate analyzers use stress cases to show how sensitive a deal is to delays, lower resale value, higher rehab costs, or local foreclosure friction. These scenarios are not predictions. They are screening tools that help a user see whether a deal has enough margin to survive bad inputs.

Known Limits

State-level defaults are not county-level quotes. Property taxes, transfer taxes, insurance premiums, title fees, recording charges, and attorney fees can vary materially by county, property type, exemption status, policy coverage, and contract terms.

For a deeper research trail, start with the state assumptions and sources page, then review the editorial policy.