Not financial advice. Mortgage FV Calculator is a software calculator, not a personal-finance product or advisory service. It computes standard financial functions and displays the results for your convenience. Nothing here constitutes, or is intended to constitute, financial, investment, tax, legal, mortgage, credit, or insurance advice. Always consult a qualified professional before making any financial decision.
5% mortgage on a $400,000 house
With 20% down ($80,000), you borrow $320,000. Over 30 years that is $1,718 a month in principal and interest, and $298,419 of interest in total.
30-year versus 15-year
| Term | Monthly P&I | Total interest |
|---|---|---|
| 30 years | $1,718 | $298,419 |
| 15 years | $2,531 | $135,497 |
The shorter term costs $813 more each month and saves $162,921 in interest.
Adding $200 a month to principal
Keeping the 30-year loan but paying $200 extra each month clears it 6 years and 2 months early and removes $70,376 of interest — a middle path between the two terms that you can stop at any time.
The same house at other rates
| Rate | Monthly P&I |
|---|---|
| 5% | $1,718 |
| 5.5% | $1,817 |
| 6% | $1,919 |
| 6.5% | $2,023 |
| 7% | $2,129 |
| 7.5% | $2,237 |
| 8% | $2,348 |
What this leaves out
These figures are principal and interest only. Property tax, homeowners insurance, HOA dues and PMI below 20% equity all add to the real monthly cost, and they vary by state and lender. Run the full calculator to add them and see the net present value of the deal.