Loan and Installment Calculator — True APR (IRR)
Find the true annual rate from the amount, term and installment, or compute the installment from a rate, to reveal the real cost of “low fee” plans.
Processed locally in your browser. Nothing is uploaded.
How to use
- Choose what to calculate.
- Enter the amount, number of payments and installment or fee rate.
- Review the true annual rate and total cost.
Example and rules
Example: $12,000 over 12 months with a 0.6% monthly fee looks like 7.2% a year, but the true APR is about 13.0%.
- The true rate is the internal rate of return × 12 (nominal APR).
- Fee mode: installment = principal ÷ periods + principal × fee per period.
- Late fees and penalties are not included.
Frequently asked questions
Why is the true rate so much higher than the fee?
The fee is charged on the full principal while the balance declines each month.
How do IRR and APR relate?
APR here is the periodic IRR × 12, without compounding.
Is anything saved?
No. Calculations stay on this page.