Mortgage Calculator
PITI, PMI, and the real monthly.
Drop in the price, the down payment, and a rate. We'll show you the full monthly payment with taxes, insurance, PMI (and when it drops off), plus a month-by-month amortization schedule and your approval odds.
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| Mo | Payment | Principal | Interest | Balance |
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Approval Odds & Expected Rate
—How This Calculator Works
Your monthly payment has four contractual pieces (principal, interest, taxes, insurance — PITI) plus two optional add-ons (PMI and HOA). Most published "mortgage calculators" show you only the principal-and-interest portion, which is typically 55–70% of what you'll actually pay. We show you all of it, starting from the moment you change a number.
The Principal & Interest Formula
We use the standard fixed-rate amortization formula:
where P is the loan amount (price minus down payment), r is the monthly interest rate (annual rate / 12 / 100), and n is the number of monthly payments (term × 12). The schedule table below the chart is generated month by month so you can see exactly how interest front-loads in the early years.
Property Tax and Insurance
Property tax is calculated as a percentage of the home's value, divided by 12. National median effective rate is roughly 0.9–1.2%, but New Jersey, Illinois, and Texas homeowners should set 1.8–2.5%. Homeowners insurance depends on replacement cost and hazard risk — $1,200–$2,200 per year is typical outside high-hurricane or wildfire zones.
PMI and When It Ends
If your loan-to-value ratio (LTV) is above 80%, conventional lenders charge private mortgage insurance. It protects the lender if you default — not you. PMI runs 0.3%–1.5% of the loan per year, tiered by credit score. The Homeowners Protection Act (HPA) requires automatic termination at 78% of the original value, and you can request removal at 80% with a solid payment history. The calculator tells you the exact month PMI drops off given your inputs.
The Credit-Risk Widget
The right-side widget estimates your odds of approval and your expected rate range. It uses three inputs — credit score, monthly income, and existing monthly debt payments — combined with the monthly payment the calculator is currently computing. The math:
- FICO tier: Exceptional (800+), very good (740+), good (670+), fair (580+), or poor (<580). Each tier has a base approval probability and a default rate band.
- DTI multiplier: Total debt (existing + new mortgage) / gross monthly income. Below 36% is ideal; above 43% is the conforming limit.
- Loan-type adjustment: Mortgage rates sit roughly 3.5 points below unsecured personal-loan rates because your house is the collateral.
Approval odds = base probability × DTI multiplier. It's a heuristic, not a lender decision — but when the widget says "borderline" at 52% DTI, actual underwriters usually agree.
How Lenders Actually Evaluate You
Underwriters look at four numbers in practice: FICO score, front-end DTI (housing cost / income), back-end DTI (all debt / income), and LTV. Conforming conventional wants 36/43% front/back DTI; FHA stretches to 31/43% with compensating factors; jumbo lenders want the cleanest profile of all. The "compensating factors" that let you exceed those limits are cash reserves (six-plus months of payments in savings) and a FICO above 780.
Choosing the Right Term
The 30-year fixed is still the American default because it maximizes monthly cash-flow flexibility. But the 15-year fixed usually carries a rate about 0.5–0.75 percentage points lower and saves six figures in lifetime interest. The key question is: can you reliably afford the 15-year payment, with a month of cushion, for the next decade and a half? If yes, take it. If there's any doubt, take the 30-year and make extra principal payments in the good years — you keep the option to back off.
15-Year vs 30-Year — A Worked Example
On a $360,000 loan at today's roughly 7.0% / 6.25% rate split:
- 30-year fixed @ 7.0% → $2,395/mo P&I, $502,234 total interest
- 15-year fixed @ 6.25% → $3,087/mo P&I, $195,614 total interest
- Extra: $692/mo in exchange for $306,620 saved over the life of the loan.
Common Mistakes to Avoid
- Ignoring PMI in the monthly number. A 5%-down loan on a $450k house adds ~$200/mo in PMI on top of P&I. Most people forget.
- Under-budgeting property tax. Tax assessments rise with comparable sales. If you're buying at the top of the market, budget a 10–15% reassessment jump in year three.
- Shopping rates on the wrong day. Mortgage rates reset every morning based on MBS pricing. The lender who quoted you Tuesday's rate on Thursday is quoting a stale number. Lock when you're ready, not when the quote is.
- Skipping closing costs. Budget 2–4% of the purchase price. The calculator does not include them — it's showing steady-state monthly cost only.
Frequently Asked Questions
What is PITI?
Principal, interest, taxes, and insurance — the four components of a typical monthly mortgage payment. PMI and HOA fees are layered on top when they apply.
When does PMI drop off?
On a conforming conventional loan, PMI automatically terminates when your loan balance reaches 78% of the original purchase price. You can request removal at 80% LTV with a solid payment history and an appraisal.
Does a higher down payment always help?
Below 20% it helps two ways: lower LTV and lower or no PMI. Above 20% the benefit is marginal — you've saved the interest on that incremental capital, which is almost always less than the return on keeping it invested.
Can I use this for an FHA or VA loan?
The P&I math is identical. But FHA and VA use different insurance structures — FHA has MIP (upfront + annual) that doesn't drop off on new loans, and VA has a funding fee with no monthly insurance. Swap the PMI line with the equivalent fee as a rough approximation.
Why is the APR field missing?
APR on a mortgage is the interest rate plus amortized closing costs. We don't ask for closing costs because they vary too much by lender and state. Use your loan-estimate APR from a real quote for apples-to-apples comparison.
Related Guides
Long-form playbooks that pair with this calculator.