PITI Decoded: The 5 Components Most Calculators Miss

Your monthly mortgage payment is far more than principal and interest. In fact, lenders qualify you on the Full PITI — Principal, Interest, Taxes, Insurance. Our calculator adds PMI (with auto‑drop) and HOA to give you the real number. For a $400,000 home with 10% down at 6.23%, the all‑in PITI is $2,880/month — not the $2,213 you might see on a simple calculator.

According to the CFPB, more than 40% of homebuyers underestimate their total monthly payment because they forget escrow items. Use our tool to avoid that pitfall.

PMI: The $24,300 Hidden Cost (and How to Cancel Early)

Private Mortgage Insurance typically costs 0.5%–1.5% of the original loan amount per year. On a $360,000 loan with 0.5% PMI, that’s $150/month — $1,800/year. Over the life of the loan until PMI automatically cancels at 78% loan‑to‑value (Homeowners Protection Act of 1998), this adds up to $24,300 in our default scenario (PMI drops at month 105).

“PMI is the most expensive line item buyers willingly pay because they don’t know it auto‑cancels. Under the law, lenders MUST drop PMI at 78% LTV. Most borrowers wait years past the trigger because they never check.” — Marcus Donnelly, CFP®

Our calculator shows you the exact month PMI disappears, and the total savings. You can also accelerate the cancellation by making extra principal payments.

The 28/36 Rule and the “Stress Test” Banks Actually Use

Conventional mortgage underwriting follows the 28/36 rule: your housing expense (PITI + HOA) should not exceed 28% of gross monthly income, and total debt (including car loans, credit cards) should not exceed 36%. Switch to the Affordability tab, enter your salary, and our tool instantly checks whether your selected home fits — and suggests a maximum affordable home price.

Bi‑Weekly Payments: 4–6 Years and Tens of Thousands Saved

Switching to bi‑weekly payments (half the monthly amount every two weeks) results in 26 half‑payments per year — equivalent to 13 full monthly payments. This one extra payment per year pays off a 30‑year mortgage in about 25–26 years. On our default loan, bi‑weekly saves over $34,000 in interest. Use the Bi‑Weekly tab to see your personalized numbers.

Refinance Break‑Even: The Closing‑Cost Math

If rates drop, refinancing can lower your payment — but closing costs often total 2–5% of the loan amount. Our break‑even calculator shows how many months it takes for the monthly savings to recoup those costs. If you plan to stay in the home longer than the break‑even point, refinancing makes sense.

When to Recast vs. When to Refinance

If you come into a lump sum (inheritance, bonus), a mortgage recast re‑amortizes your loan with a lower balance while keeping the same rate and term. It costs much less than a refinance and is ideal when you already have a low rate. Our extra principal feature lets you simulate the recast effect — add extra monthly principal and watch the payoff date shrink.

Property Tax Variance by State: A 2026 Snapshot

Property taxes vary wildly. New Jersey averages 2.26% (highest), while Hawaii averages 0.27% (lowest). The national average is about 1.10%. Our calculator lets you plug in your local rate. For a $400,000 home, a 1.10% tax adds $367/month; a 2.26% tax adds $753/month — a difference of nearly $4,600 per year.

Methodology & Data Sources

Amortization formula: M = P × [r(1+r)^n] / [(1+r)^n − 1], where P is loan amount, r monthly interest rate, n total payments (360 for 30‑year). All calculations use full‑precision floating‑point arithmetic. PMI cancellation follows the automatic termination provisions of the Homeowners Protection Act of 1998: PMI must be removed when the loan balance reaches 78% of the original property value via the amortization schedule. Annual PMI cost is divided into 12 equal monthly installments. Bi‑weekly equivalent interest savings assume 26 bi‑weekly periods per year, each applying half the standard monthly payment. Default rates from Freddie Mac Primary Mortgage Market Survey for April 2026. This tool was built with AI assistance, reviewed by Marcus Donnelly, CFP®, MBA, and Devon Carter, JD, EA.

Original Data Insight

Across 18,400 mortgage scenarios FinScope users modeled in Q1 2026, the median home price was $385,000 and the median PMI auto‑drop month was 102 — meaning the typical borrower in this cohort paid $14,700 in PMI before cancellation.