home / mortgage loan
// the real cost of your home loan
What does your mortgage really cost?
A 30-year mortgage often costs more in interest than the amount you borrowed. See your number, then see how to shrink it.
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Results update live. Math runs in your browser — nothing is sent anywhere.
⚡ What if you paid extra?
save $0Where every dollar paid has gone — principal vs interest
| Year | Principal | Interest | Cum. Interest | Balance |
|---|
Mortgage toolkit
Every lever that changes what your home loan costs.
Extra Payments
Interest saved & years cut, live.
15 vs 30 Year
Side-by-side totals with dual chart.
Biweekly Payments
What the 13th payment is worth.
Refinance Break-Even
Closing costs vs interest saved.
PMI Removal Date
Your 80%/78% dates & the appraisal shortcut.
Full Schedule
Year-by-year table, CSV & PDF.
Payoff vs Invest
The dilemma, refereed fairly — find your breakeven return.
Pre-computed reference tables
Exact total-interest figures, ready to read — no inputs needed.
''' + RT_INDEX + AMT_INDEX + '''Frequently asked questions
Why is mortgage interest so high over 30 years?
Because the balance stays large for years. Early payments are mostly interest; on a 6.5% 30-year loan you don't pay more principal than interest until well past year 15.
Do extra payments really help on a mortgage?
Yes — disproportionately. Extra payments go entirely to principal, shrinking the balance every later interest charge is computed on. $200/month extra on a $400k loan typically saves six figures.
Does this include taxes, insurance and PMI?
No — deliberately. Those are costs of owning, not costs of borrowing. This tool isolates the interest so you can see the loan itself clearly.
What is the principal-vs-interest crossover?
The first month your payment puts more toward principal than interest. We mark it on the chart; moving it earlier is the whole game.
📖 Related guide: Why you pay mostly interest in the early years