Calculation Methodology

Two-layer verification

Most results appear instantly in your browser, then the same scenario is recalculated by our versioned server formula. A “verified” result means those two calculations agree; it does not mean a lender has approved the scenario.

Math and rounding

Server calculations use decimal arithmetic for money and explicit half-up rounding to cents. Fixed-rate payments use the standard amortizing-loan formula. Amortization schedules reconcile the final payment so principal totals the original balance.

Assumptions and sources

Each result includes its formula version, effective date, assumptions, and source links. Government-backed tools use official HUD or VA rules identified on their page. Editable taxes, insurance, fees, appreciation, rent growth, and market assumptions are estimates—not live quotes.

Known boundaries

• We do not determine underwriting, creditworthiness, or program eligibility.
• Local taxes, insurance, HOA dues, and closing practices require local quotes.
• Tax benefits are excluded unless a calculator explicitly says otherwise.
• Results may differ from lender systems because of dates and rounding policy.

Start with a calculator

Browse all ten tools on the calculator directory. Every page exposes the assumptions used for that specific estimate.