Amortization logic
The calculator estimates a standard amortizing loan using the stated principal, rate, and term. It can also model extra monthly payments, a single one-time extra payment, and recurring annual lump-sum payments.
Rate scenario cards compare base, lower, and higher rates using the same balance and term structure for planning purposes.
True monthly cost layer
Property tax, homeowners insurance, HOA dues, and PMI are shown as affordability inputs. These values help estimate the real monthly ownership cost even though they do not usually reduce loan principal.
State page benchmarks
State pages use broad planning benchmarks for median home price, effective property tax rate, and typical insurance cost. They are not property-specific quotes and should be treated as high-level screens before lender or insurer confirmation.