What your monthly payment includes
The headline figure is principal and interest, but real housing costs also add property taxes, homeowner's insurance and any HOA dues — this calculator folds them in so the estimate matches what you would actually pay each month.
How term and rate interact
A shorter term raises the required payment but slashes lifetime interest; a lower rate achieves the same without stretching your timeline. Compare 15 vs 30 years by adjusting the term field and watching total interest move.
Below a 20% down payment most lenders also add PMI, which is not estimated here — treat sub-20%-down results as slightly optimistic until you have a lender quote.