Interest Rate Calculator
Dealers love advertising '$399/month' without the rate. Enter the financed amount, term, and that payment to reveal the implied APR — then compare against bank pre-approval offers.
Implied annual rate
6,000%
- Effective annual rate (EAR)
- 217,678,233,500%
- Total of payments
- $29,700.00
How the Interest Rate Calculator works
The calculation follows the standard method used across the US — no shortcuts, no hidden assumptions. Here is exactly what happens behind the scenes:
Formula
Solve PMT = P·i/(1−(1+i)^−n) for i via bisection
Frequently Asked Questions
Can the rate be negative?
If the total of payments is less than the amount borrowed, the implied rate is zero or negative — typically meaning a subsidy or an input error.
Does this include fees?
No — this solves the note rate. Fees belong in APR calculations; try our APR Calculator for fee-inclusive comparisons.
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