Home Down Payment Mathematics & PITI Housing Formulas
Home purchase financing balances upfront liquidity with monthly mortgage amortization and PMI obligations:
1. Upfront Down Payment & Loan Principal
Down Payment = Purchase Price ×
Down %100
; Loan Principal = Purchase Price - Down Payment2. All-Inclusive Monthly Housing Cost (PITI + PMI)
Total Monthly Check = Monthly P&I + (Annual Taxes & Insurance / 12) + Monthly PMI
Step-by-Step Down Payment Breakdown
Step 1: Calculate Required Upfront Cash Down Payment
$450000 price × 20% = $90,000 upfront cash (Leaves $360,000 mortgage debt).
Step 2: Monthly Principal & Interest (P&I)
Amortized over 30 years @ 6.75% = $2,335 / month.
Step 3: Total All-In Monthly Housing Commitment
Total Monthly Housing=$2,935 / mo (Zero PMI Required)
Down Payment Tiers & Loan Program Guidelines
| Mortgage Program | Minimum Down Payment | Mortgage Insurance Rules | Best Suited For |
|---|---|---|---|
| Conventional Conforming | 3% to 5% | PMI required if down < 20% (cancels at 80% LTV) | Borrowers with 680+ credit scores |
| FHA Loan (Federal Housing) | 3.5% | Upfront MIP (1.75%) + Annual MIP for life of loan | First-time buyers with 580+ credit |
| VA Loan (Veterans Affairs) | 0% Down | No monthly PMI (One-time VA Funding Fee applies) | Eligible military service members & veterans |
| 20%+ Equity Conventional | 20.0% | Zero PMI from Day 1 | Buyers seeking lowest monthly outlay |