Decision tools built for clarity
Mortgage Calculator
Estimate a fixed-rate monthly mortgage payment and review the bounded payment schedule.
Enter the home price, down payment, annual rate, term, start date, and any optional monthly housing estimates.
Taxes, insurance, and HOA amounts are estimates, not a lending offer.
Methodology
Formula or transformation
Uses the fixed-rate amortization relationship for periodic principal and interest, then adds only the submitted monthly cost estimates.
Variables
- Home price
- Down payment
- Annual interest rate as a percentage
- Term in years
- Start date
- Monthly property tax estimate
- Monthly insurance estimate
- Monthly HOA estimate
Units
- Currency
- Percent
- Years
- Calendar date
Rounding policy
Money values are rounded to the declared currency scale using half away from zero; the bounded schedule reconciles the final payment.
The estimate follows a fixed-rate monthly repayment schedule and separates principal, interest, and optional housing costs.
Estimate monthly principal and interest, total housing cost, total interest, repayment, and a bounded payment schedule.
Reviewed sources
- CFPB — How paying down a mortgage works Reviewed on 2026-09-04
- CFPB — Principal and interest versus total monthly payment Reviewed on 2026-09-04
Formula review history
-
Initial formula and source review.
Reviewed 2026-09-02 for formula version fixed-rate-monthly-amortization-v1
-
Confirmed formula identity, sources, rounding, and public disclosure.
Reviewed 2026-09-04 for formula version fixed-rate-monthly-amortization-v1
Assumptions
- The interest rate and scheduled monthly principal-and-interest payment remain fixed.
- Taxes, insurance, and HOA entries are monthly estimates in the selected currency.
Limitations
- The estimate excludes lender fees, closing costs, rate changes, and prepayment effects.
- It is an educational payment estimate and is not a lending or financial offer.
Worked example
For a 100,000 loan at a 6% annual fixed rate over 30 years, estimated monthly principal and interest is 599.55 before other housing costs.
Frequently asked questions
Does the monthly payment include every housing cost?
Only the optional monthly estimates you enter are added; other costs may still apply.
Is the schedule a lender quote?
No. It is a bounded educational estimate based on the submitted assumptions.