PMI计算器公式

## What Is Private Mortgage Insurance?

PMI is required by conventional lenders when the down payment is less than 20% of the home value. It protects the lender if you default on the loan.

### How PMI Is Calculated

**Monthly PMI = (Loan Amount x Annual PMI Rate) / 12**

### PMI Rate Factors

- **Loan-to-value ratio**: Higher LTV means higher PMI rates
- **Credit score**: Better credit lowers your PMI rate (0.3% to 1.5% annual range)
- **Loan type**: Fixed-rate loans have lower PMI than adjustable-rate

### Removing PMI

You can request PMI removal when your LTV reaches 80%. It is automatically cancelled at 78% LTV based on the original amortization schedule.

计算示例

A $400,000 home with $40,000 down (10%), PMI rate of 0.55%, 7% interest, 30-year term.

  1. Loan amount: $400,000 - $40,000 = $360,000
  2. LTV: $360,000 / $400,000 = 90%
  3. Annual PMI: $360,000 x 0.55% = $1,980
  4. Monthly PMI: $1,980 / 12 = $165.00
  5. Monthly P&I: $2,395.09
  6. Total monthly with PMI: $2,395.09 + $165.00 = $2,560.09