贷款摊销计算器 — 公式

How Loan Amortization Works

Amortization is the process of spreading loan payments over time. Each payment covers interest on the remaining balance plus a portion of the principal.

Formula

Monthly Payment: M = P * [r(1+r)^n] / [(1+r)^n - 1]

For each payment:

  • Interest portion = Remaining balance * monthly rate
  • Principal portion = Monthly payment - interest portion

    • Early payments are mostly interest; later payments are mostly principal.

    计算示例

    A $200,000 loan at 6% interest for 30 years.

    1. Monthly rate: 6% / 12 = 0.5% (0.005)
    2. Total payments: 30 * 12 = 360
    3. Monthly payment = $200,000 * [0.005 * (1.005)^360] / [(1.005)^360 - 1] = $1,199.10
    4. First month interest: $200,000 * 0.005 = $1,000.00
    5. First month principal: $1,199.10 - $1,000.00 = $199.10
    6. Total paid: $1,199.10 * 360 = $431,676.00
    7. Total interest: $431,676.00 - $200,000 = $231,676.00