Methodology
How the calculators work
Home Calculator uses standard educational formulas and user-entered assumptions. Results are estimates and are not a loan quote or financial advice.
Simple mortgage payment
The simple calculator estimates monthly principal and interest using the standard amortizing loan formula:
M = P × r(1+r)^n / ((1+r)^n - 1)
Where P is loan amount, r is monthly interest rate, and n is the number of monthly payments.
Realistic monthly cost
The realistic calculator adds:
- Principal and interest
- Estimated monthly property tax
- Homeowners insurance
- Estimated PMI when down payment is below 20%
- HOA dues
- Utilities
- Maintenance reserve
- Lawn care
Affordability status
The status uses broad housing-ratio and debt-to-income thresholds. Lenders, loan programs, credit profiles, taxes, insurance, and local property conditions vary widely. A result that appears comfortable may still be inappropriate for a user's personal budget.
Cash needed
Cash needed is estimated as down payment plus a rough 3% closing-cost assumption. Actual closing costs vary by market, lender, loan type, prepaid taxes, escrow reserves, insurance, transfer taxes, and negotiated credits.