Payment math
Principal and interest use standard fully amortizing mortgage math over the selected loan term. Taxes, insurance, PMI, and HOA are displayed as separate monthly ownership costs.
Built for clarity
MortgageCalcGrid is designed to make the assumptions visible. You can edit the inputs, test scenarios, and take the final numbers to licensed professionals for review.
Build a planning reportPrincipal and interest use standard fully amortizing mortgage math over the selected loan term. Taxes, insurance, PMI, and HOA are displayed as separate monthly ownership costs.
State-level property-tax and homeowners-insurance assumptions help create a starting point. They are estimates only and remain editable in every report.
Enhanced New York, California, and Massachusetts models separate supported statutory calculations from editable lender, title, professional, prepaid, recording, and local estimates. Other states use clearly labeled planning assumptions.
The comparison models each path month by month, including mortgage amortization, complete housing costs, transaction costs, home-value and rent changes, selling costs, and the potential return on invested cash differences.
Refinance results compare both monthly cash flow and remaining loan balances. Closing costs remain an economic cost when financed, and the payoff-timeline impact stays visible.
Both strategies receive the same lump sum and monthly cash budget. The model follows mortgage balances, interest, investment growth, fees, tax drag, and post-payoff investing month by month, with conservative and optimistic return scenarios.
Comfort ranges weigh income, monthly debt, down payment, credit, remaining reserves, and payment size. They are planning signals, not underwriting decisions.
What the report does not do
Interest rates are user-entered planning inputs. MortgageCalcGrid does not provide live rate quotes, pre-approvals, or rate locks.
Five-year equity examples use a 3.0% annual home-value growth assumption. Future home values, taxes, insurance, and loan terms can change.
Rent-vs-buy projections are scenarios, not forecasts. Home values, rents, investment returns, taxes, insurance, repairs, and transaction costs can differ materially.
Closing costs are location-aware estimates. Official Loan Estimates, Closing Disclosures, title documents, insurance quotes, and tax records control.
Refinance estimates depend on user-entered rates, terms, costs, credits, and horizon. APR, escrow adjustments, prepaids, payoff statements, and lender disclosures can materially change the outcome.
Invest-vs-paydown results are scenarios, not forecasts. Market returns, taxes, fees, liquidity needs, deduction eligibility, and account-access rules can materially change the result.
Before committing to a purchase or mortgage, compare official Loan Estimates and speak with appropriate licensed professionals. See the full calculator disclaimer.