Math the monthly nut before you sign.

How the calculator works

The principal & interest portion uses the standard amortization formula: P = L · r / (1 - (1 + r)^-n), where L is the loan amount, r is the monthly rate (APR / 12), and n is total months. Property tax and insurance are spread evenly across 12 months and added on top to produce PITI — the all-in monthly payment most lenders will quote you.

What's not included

PMI (private mortgage insurance) kicks in when your down payment is below 20% — typically 0.3-1.5% of the loan annually, dropping off when you cross 78% LTV. HOA fees vary widely by community. Closing costs (2-5% of the loan) are paid up front, not in the monthly payment. For a deeper walkthrough see our home loans guide.

Why the same APR can produce wildly different monthly payments

Term length is the lever most buyers underestimate. A $320,000 loan at 6.75% APR over 30 years runs about $2,076 monthly P&I — same loan over 15 years runs $2,832. The 15-year payment is 36% higher, but lifetime interest drops from $427,000 to $189,000. Slide the term above to see the trade-off in real time.