Interest Rate Calculator
Find the annual interest rate on a loan given the principal, monthly payment, and term. Uses Newton's method for precise results.
How to Use the Interest Rate Calculator
- Enter the required financial values such as amount, rate, or term.
- Adjust additional parameters if available (e.g., down payment, fees).
- The result updates automatically as you type.
- Review the calculated figures including breakdowns and totals.
Quick Reference
| From | To |
|---|---|
| $1,000 · 5% · 1yr | $1,050 |
| $5,000 · 4% · 3yr | $5,624 |
| $10,000 · 6% · 5yr | $13,382 |
| $10,000 · 3% · 10yr | $13,439 |
| $25,000 · 5% · 10yr | $40,722 |
| $50,000 · 7% · 20yr | $193,484 |
Use Cases
- •Evaluating different loan or mortgage options before making a decision.
- •Planning a monthly budget with accurate payment projections.
- •Estimating long-term investment growth or retirement savings.
- •Comparing interest rates and total costs across financial products.
Formula
Solve for r in: P × r × (1+r)^n / ((1+r)^n − 1) = M, where P is principal, M is monthly payment, n is term in months. Annual rate = r × 1200.
Frequently Asked Questions
How to use?
Enter the data and click the calculate button.
Calculation accuracy?
Calculations are performed with high precision using Newton's iterative method.
Is it free?
Yes, all calculators are completely free.