Loan Interest Rate Calculator
Find the effective interest rate behind a loan amount, EMI, and tenure. Free online loan interest rate calculator.
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$
mo
P × r × (1 + r)^n / ((1 + r)^n − 1) = EMI
100000 × 0.014395 × (1 + 0.014395)^n ÷ ((1 + 0.014395)^n − 1) ≈ 2500.00
17.27%
Approximate Annual Interest Rate
Monthly Interest Rate
1.439%
Total Amount Payable (EMI × n)
$150000.00
Total Interest
$50000.00
How Does the Loan Interest Rate Calculator Work?
Given a loan amount, a fixed monthly payment (EMI), and a tenure in months, this calculator works out the implied annual interest rate. The monthly payment satisfies the EMI formula P × r × (1 + r)^n / ((1 + r)^n − 1), where P is the loan amount, r the monthly interest rate, and n the number of months. Because the formula cannot be rearranged to solve for r directly, the calculator finds r numerically using a bisection method: it brackets the monthly rate between a low and a high guess, then repeatedly halves the range until the formula reproduces your EMI to within a tiny margin. The estimated rate is then converted to an annual figure by multiplying by 12, so the result is an approximation, not an exact closed-form answer.
Example
Borrow $100,000 over 60 months with a $2,500 monthly payment. Trying monthly rates step by step, a rate near 1.44% per month reproduces the $2,500 EMI almost exactly, so the annual rate works out to roughly 17.27%. Over the loan your total payments come to $150,000, of which $50,000 is interest. A lower payment stretches the same loan to a lower implied rate, and a higher payment implies a higher rate.
Common Use Cases
- Benchmarking an existing loan offer against advertised interest rates.
- Checking whether a quoted EMI implies a fair rate before signing.
- Comparing personal loan or auto loan offers with different fees bundled in.
- Understanding how much interest a fixed monthly commitment really costs.
FAQs
Why is the result only approximate?
The EMI formula cannot be solved for the interest rate with a simple formula. The calculator estimates it with an iterative bisection search, which gets closer with each step but never reaches an exact value. For practical purposes the result is accurate to several decimal places.
What if my EMI is too low to find a rate?
Every loan has a minimum payment equal to the principal divided by the number of months — the amount needed if interest were zero. If your EMI is below that, no positive interest rate can match it, and the calculator shows the error instead of inventing a rate.
Does the calculator account for prepayment or bank fees?
No. It assumes a fixed EMI with no early repayment and no processing or administrative fees folded into the payment. Such fees would widen the gap between the quoted rate and your effective rate.