StraightToolsMortgage Calculator
Estimate monthly principal and interest for a fixed-rate mortgage.
What this estimate includes
This calculator shows principal and interest only. Property tax, homeowners insurance, mortgage insurance, HOA fees, and closing costs are not included.
When to use this tool
Use the mortgage calculator to estimate the principal-and-interest portion of a fixed-rate home loan. It is useful for comparing loan amounts, rates, and terms before you ask a lender for a formal quote.
How the result is calculated
The calculator uses the standard amortizing-loan formula. The monthly interest rate is the annual percentage rate divided by 12, and the payment spreads principal and interest across the selected number of monthly payments.
Worked example
A $400,000 mortgage at 6.5% for 30 years produces a principal-and-interest payment a little above $2,500 per month. Shorter terms generally raise the monthly payment but reduce total interest.
What to keep in mind
A real housing payment can also include property tax, homeowners insurance, mortgage insurance, HOA dues, lender fees, and escrow adjustments. This tool is educational and is not a loan offer or financial advice.
About our calculations
StraightTools is designed to show the method behind the answer, not just the result. Inputs are handled in your browser for this tool. For important financial, legal, medical, tax, safety, or contractual decisions, verify the result with an appropriate authoritative source or qualified professional.