Financial
Interest Rate Calculator
Solve for the implied annual interest rate on a loan from the payment amount.
Inputs
Interest Rate Calculator
Result
Annual interest rate
7.42%
- Monthly rate
- 0.6183%
- Total paid
- $24,000.00
- Total interest
- $4,000.00
How it's calculated
Solve r in P = PMT · (1 − (1+r)^−n)/r via bisection
Common questions
Why bisection?
The amortization formula has no closed-form solution for r; bisection reliably converges within tens of iterations.
Is this the APR?
It's the nominal annual rate from the payment. APR also includes fees; use the APR calculator when fees are known.
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