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Rule of 78 Unearned Interest Calculator

Unearned interest rebate when prepaying a loan early.

Compute the unearned-interest rebate on a fixed-term loan if you prepay it early under the Rule of 78s, used by some auto and personal lenders. Returns the rebate factor and the rebate amount.

Nadia Almasri By Nadia Almasri
Published Last reviewed 1 min read

Inputs

$

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

Rebate factor = (m · (m + 1)) / (n · (n + 1)), m = remaining payments, n = total payments. Rebate = factor · total_finance_charge.

In depth

Compute the unearned-interest rebate on a fixed-term loan if you prepay it early under the Rule of 78s, used by some auto and personal lenders. Returns the rebate factor and the rebate amount.