Mortgage Calculator Estimate payments, interest, and payoff timelines — with refinancing, extra payments, and affordabili...
Mortgage Calculator
Estimate payments, interest, and payoff timelines — with refinancing, extra payments, and affordability analysis.
A mortgage is an amortizing loan where each payment covers:
- Principal: Reduces your debt
- Interest: Cost of borrowing (higher early on)
- Taxes & Insurance (PITI): Often paid via escrow
Example: $320K loan @ 6.8% for 30 yrs: • Payment 1: $1,812 interest, $374 principal • Payment 120 (10 yrs): $1,530 interest, $656 principal • Payment 360 (30 yrs): $18 interest, $2,168 principal
✅ Pro Tip: Extra payments early save the most — because you reduce the balance when interest is highest.
⚠️ Watch for these risky features:
- Negative Amortization: Payment < interest → balance grows (common in option ARMs).
- Teaser Rates: Low intro rate, then jumps 2–4% (e.g., 3.5% → 7.5% after 5 yrs).
- Prepayment Penalties: Fee for refinancing/early payoff (check your contract!).
- Interest-Only Periods: 5–10 yrs at $1,800/mo, then jumps to $2,600/mo.
✅ Always ask: “Are there prepayment penalties? Is this a fixed or adjustable rate?”
| Term | Avg. Rate | Payment on $320K |
|---|---|---|
| 30-Yr Fixed | 6.8% | $2,086/mo |
| 15-Yr Fixed | 6.0% | $2,712/mo |
| 5/1 ARM | 5.8% (intro) | $1,877/mo (first 5 yrs) |
📉 Savings Tactics: • **Bi-weekly**: Pay half-monthly every 2 weeks → **$83K interest saved** • **$200/mo extra**: Cuts 30-yr to **22.3 years**, saves **$64K interest** • **Refinance from 7.5% → 5.8%**: Saves **$175/mo**, break-even in **2.1 years**
➡️ Standard
Enter home price, down payment, rate, and term to get full PITI payment and amortization.
➡️ Extra Payments
Test lump sums (bonus, inheritance) or recurring extra payments.
➡️ Refinance
See monthly savings, break-even point, and total interest saved.
➡️ Affordability
Determine how much home you can afford based on income and DTI rules.
Note: Assumes fixed rate, no fees unless specified. ARM scenarios require manual modeling.