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What this U.S. mortgage calculator gives you
A U.S. mortgage is a 15-, 20-, or 30-year fixed-rate (or adjustable) loan secured by your home. The monthly payment that lenders quote is almost always the P&I portion only — principal plus interest. Your real housing cost includes property tax, homeowner insurance, and (if applicable) PMI and HOA dues. This mortgage calculator shows the P&I number with precision and gives you the framework below to add the other components for a complete PITI estimate.
It's calibrated for U.S. defaults — 30-year terms, fixed rates around the recent Freddie Mac PMMS averages, and dollar formatting. International borrowers can switch the currency and locale, or use our global home loan EMI calculator or India home loan EMI calculator instead.
How to use this mortgage calculator
- Start with the home price minus your down payment — that's the loan amount.
- Enter the rate from a written Loan Estimate, not a verbal dealer quote. Lenders are required to deliver a Loan Estimate within 3 business days of application under CFPB rules.
- Pick the term — 30 years is the U.S. default. Try 15-year and 20-year scenarios with the quick chips.
- Read the three results. Monthly payment is your cash-flow number; total interest is your true cost number.
- Add your other PITI components manually using the rules below, then check that the total stays inside 28–35% of your gross monthly income.
Worked example: a $400,000 U.S. mortgage at 6.75% for 30 years
Assume a $500,000 home with a 20% down payment, financing $400,000 at 6.75% for 30 years:
- P&I monthly payment ≈ $2,594
- Total interest over 30 years ≈ $533,945
- Total repayment ≈ $933,945
Add a typical 1.1% effective property tax rate ($458/month on a $500K home), $145/month homeowner insurance, and assume 20% down so no PMI. The full PITI ≈ $3,197/month. To stay inside the conservative 28% front-end DTI ratio, you'd want a household gross income around $11,400/month (~$137K/year). That gap between the headline P&I number and the real cost of homeownership is what catches most first-time U.S. buyers off-guard.
PITI vs P&I: what's actually in your monthly payment
| Component | What it is | Typical monthly cost |
|---|---|---|
| P&I | Principal + interest from this calculator | $1,800–$3,500 on a typical home |
| Property tax | Local tax based on assessed value | 0.3–2.3% of home value per year, ÷ 12 |
| Homeowner insurance | Required by lender | $80–$200/month |
| PMI (if < 20% down) | Insures lender against default | 0.5–1.5% of loan/year, ÷ 12 |
| HOA (if applicable) | Condo / community fees | $50–$700/month |
15 vs 20 vs 30-year mortgage comparison
The same $400,000 mortgage at currently realistic U.S. rates per term:
| Term | Rate | Monthly P&I | Total interest |
|---|---|---|---|
| 15 years | 6.00% | $3,376 | ~$207,711 |
| 20 years | 6.50% | $2,983 | ~$315,789 |
| 30 years | 6.75% | $2,594 | ~$533,945 |
The 15-year term saves roughly $326,000 in interest over the life of the loan vs the 30-year — but the monthly payment is ~30% higher. Many borrowers split the difference: take the 30-year for safety, then treat the 15-year payment as a target by paying extra principal voluntarily whenever cash flow allows.
Down payment, PMI, and DTI
U.S. conventional loans typically require 5–20% down. Reaching 20% avoids PMI, which adds 0.5–1.5% of the loan balance per year. FHA loans allow 3.5% down with a 580+ FICO; VA and USDA loans can be 0% down for eligible borrowers but have their own funding fee or guarantee fee.
Most lenders cap the front-end DTI (housing payment / gross income) at 28–31% and the back-end DTI (all debt payments / gross income) at 43–45%. Keeping below those numbers is the difference between an approval and a rejection, regardless of credit score.
Mortgage points and APR
A discount point is a fee equal to 1% of the loan, paid up front, that typically lowers the rate by about 0.25%. The break-even calculation is simple: divide the upfront point cost by the monthly savings to find how many months until you recoup the cost. If you'll keep the loan longer than the break-even, points usually win. Always compare lenders by APR — which legally must include points, origination fees, and certain mortgage insurance — rather than the headline rate alone.
Common U.S. mortgage mistakes
- Comparing headline rates instead of APRs. Two loans with identical rates but different points can have very different effective costs.
- Forgetting PITI when budgeting. Your true housing payment is 20–35% higher than the P&I you see here.
- Stretching to a 30-year mortgage you can “barely afford.” Real life adds expenses; aim well inside the DTI cap.
- Putting 20% down when an emergency fund is empty. PMI is recoverable; bankruptcy is not.
- Locking the rate without three quotes. CFPB's own buyer guide recommends three lenders minimum.
- Closing on an ARM you don't understand. Ask explicitly: what's the rate cap, the reset frequency, and the worst-case payment?
Considering refinancing later?
See if a future refinance pays for itself once closing costs are factored in.
Frequently asked questions
How is a U.S. mortgage payment calculated?
Standard U.S. fixed-rate mortgages use monthly amortization: payment = P × r × (1+r)n / ((1+r)n − 1). Property tax, insurance, and PMI are added separately for the full PITI.
What is PITI?
Principal + Interest + Property Tax + Insurance. Many lenders escrow the tax and insurance portion, collecting it monthly with the loan payment.
How much down payment do I need on a U.S. mortgage?
Conventional loans typically need 5–20% down (20% to avoid PMI). FHA accepts 3.5% with a 580+ FICO; VA/USDA can be 0% for eligible borrowers.
What is PMI and how do I avoid it?
Private mortgage insurance, required on most conventional loans with <20% down. Costs 0.5–1.5% of the loan balance/year. Stops at 20% equity (request) or 22% (automatic per federal law).
15-year or 30-year mortgage?
15-year saves dramatically on interest and usually offers a lower rate. The trade-off is a higher monthly payment. Take the shortest term whose payment fits inside 28–35% of gross income.
What is APR vs interest rate?
The interest rate calculates the payment. APR includes the rate plus points, origination fees, and certain other costs — better for comparing offers.
Should I pay points to lower the rate?
Each point costs 1% of the loan and lowers the rate ~0.25%. Worth it only if you'll keep the loan longer than the break-even months.
Are closing costs in this calculator?
No. Closing costs run 2–5% of the loan. Add them to the principal field if your lender rolls them in.
Can I make extra principal payments?
Yes — almost all U.S. fixed-rate mortgages allow it without penalty. Even $100–200 extra/month saves tens of thousands across a 30-year loan.
How accurate is this mortgage calculator?
The math is exact for principal and interest. Real lender disclosures may differ slightly due to fees, daily-vs-monthly accrual, or rounding. Compare lenders by APR, not headline rate.
Sources & further reading. CFPB Loan Estimate · Freddie Mac PMMS via FRED · Federal Reserve · Internal: Understanding amortization, When refinancing makes sense, Amortization schedule calculator.