The Complete Mortgage Guide (2026)

1. What a Mortgage Payment Actually Contains (PITI)

The quoted payment is only principal and interest (P&I). Your real monthly cost — PITI — adds property taxes, homeowner's insurance, and HOA dues; below 20% equity it also adds PMI. Two houses with the same P&I can differ by $400+/month in true cost because of taxes and insurance in different ZIP codes.

Early payments are mostly interest: on a 30-year loan at 6.5%, month one of a $320,000 loan contains ~$1,733 interest and ~$290 principal. Every extra dollar paid early removes an entire future month of compounding — which is why prepayment math favors the early years so heavily.

• Principal — the borrowed amount, reduced by each payment
• Interest — the lender's charge, front-loaded in the schedule
• Taxes — 0.5-2.5% of home value yearly, varies enormously by state
• Insurance — homeowner's policy plus flood/wind where required
• PMI — 0.5-1.5%/yr of the loan while equity is under 20%

How Rates Are Set — and How to Shop Them

Mortgage rates track the 10-year Treasury yield plus a spread that widens with market uncertainty and your credit profile. They move daily — Freddie Mac's weekly survey is the standard reference. Your personal rate depends on credit tier (760+ unlocks the best pricing), down payment, loan type, and points paid.

Rate shopping works because lenders price the same borrower differently. Get 3-5 Loan Estimates within a 14-day window (credit bureaus count them as one inquiry), compare APR — not just rate — and make lenders compete on the same day, since rates move between days.

The Levers That Save the Most Money

Ranked by typical impact for a $400k, 30-year loan:

• Term (30y → 15y): saves ~$240k interest at current spreads, costs +$690/mo
• Rate (6.5% → 5.5%): saves ~$92k interest, $257/mo
• Down payment 20%+: kills PMI ($150-400/mo) but costs liquidity
• One extra payment/year: cuts ~6 years and ~$95k interest
• Refinance at −1%: saves ~$250/mo at 30y scale — worth it if staying 2+ years past break-even

Affordability — The Numbers Lenders Use

Lenders cap housing cost at 28% of gross income and total debt at 36-43% (DTI). On $100,000 income that is ≈ $2,333/month of PITI max. The smarter personal ceiling is 25% of gross, leaving room for maintenance (budget 1-2% of home value yearly) and life.

First-time buyers: FHA allows 3.5% down (with MIP for the life of the loan), conventional minimums are 3% (with PMI until 20% equity), VA and USDA loans offer zero-down for eligible borrowers. Compare total cost of each path with the loan comparison calculator — the insurance structures differ as much as the rates.