How to use this calculator
Estimate a monthly home payment, compare extra payments, and see an amortization schedule. Enter home price ($), down payment ($), annual interest rate (%), term (years), annual property tax ($), annual homeowners insurance ($), monthly hoa dues ($), monthly mortgage insurance ($), extra principal each month ($). The result updates when you change an input. To compare two sets of inputs, save scenario A, then enter the second set; the result panel shows the difference.
Formula and limits
Loan amount = home price − down payment. Monthly principal and interest uses P × r ÷ [1 − (1+r)^−n], where r = annual interest rate ÷ 1200 and n = years × 12; at zero interest it is P ÷ n. Estimated monthly total = principal and interest + annual property tax ÷ 12 + annual homeowners insurance ÷ 12 + monthly HOA dues + monthly mortgage insurance. Extra principal is applied after each scheduled monthly payment and can shorten the payoff period; it is not included in the estimated base monthly housing payment. This assumes a fixed interest rate and constant entered costs. It excludes closing costs, utilities, maintenance, changing tax or insurance bills, and any future removal of mortgage insurance. The interest rate is an input, not a current offer or fee-inclusive APR.
Worked example
The following example uses the calculator’s starting values. It is an illustration of the method, not a recommended target.
| Input | Example value |
|---|---|
| Home price ($) | 350000 |
| Down payment ($) | 70000 |
| Annual interest rate (%) | 6.5 |
| Term (years) | 30 |
| Annual property tax ($) | 4200 |
| Annual homeowners insurance ($) | 1800 |
| Monthly HOA dues ($) | 0 |
| Monthly mortgage insurance ($) | 0 |
| Extra principal each month ($) | 0 |
Estimated monthly housing payment: $2,269.79
Principal + interest: $1,769.79 · Property tax: $350.00 · Insurance: $150.00 · HOA: $0.00 · Mortgage insurance: $0.00 · Loan amount: $280,000.00 · Interest over full term: $357,124.57
Interpreting your result
The monthly total includes principal and interest plus the entered estimates for property tax, insurance, HOA dues, and PMI. Compare the total with your budget, and compare total interest when changing the term or rate. Tax, insurance, HOA, and PMI amounts can change; PMI is not removed automatically. Extra principal payments can shorten the loan and reduce interest; the payment schedule below shows their effect.
Comparing alternatives
Save the first result as scenario A, then change one input. The comparison shows the numeric difference; it does not label either result as better. Choose inputs that describe realistic alternatives. Values shown on screen are rounded, so calculations from rounded intermediate results may differ slightly.
Background reading
Investor.gov financial tools. This is a subject reference, not an endorsement or independent review of Calcaven.