Loans & mortgages · NUMORA
Effective Rate Calculator
Back-solve APR from principal, payment, term.
Open interactive calculatorHow to use
Newton solve for r in the PMT equation.
Formula
PMT = P r (1+r)^n / ((1+r)^n−1)
FAQ
Is this Effective Rate calculator accurate?
The formula and assumptions are shown on the page, and the engine is covered by audit tests. Results are for reference — not financial or medical advice.
Do I need an account?
No. Calculations run in your browser. Recents can stay on this device.
What inputs do I need?
Newton solve for r in the PMT equation.
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