What Is an Interest Rate?
In plain English
An interest rate is the percentage of the principal that a lender charges a borrower for the use of money, expressed on an annual basis. It determines how much borrowing costs beyond the original loan amount. Interest rates vary based on the type of loan, the borrower's creditworthiness, loan term, and prevailing economic conditions set by the Federal Reserve.
What Is the Difference Between Interest Rate and APR?
The interest rate reflects only the cost of borrowing the principal. The annual percentage rate (APR) includes the interest rate plus fees, points, and other financing costs, giving a more complete picture of what a loan truly costs per year. Many professionals suggest comparing APRs — not just stated interest rates — when evaluating loan offers from different lenders, as fees can significantly affect the true cost.
How Do Interest Rates Affect Your Monthly Payment?
Even small differences in interest rate have a large impact on both monthly payments and total cost over the life of a loan. On a $300,000 30-year mortgage, a rate of 6% results in about $1,799 per month; at 7%, the payment rises to approximately $1,996. Over 30 years, that 1% difference costs an additional $71,000 in total interest. Rate shopping is one of the highest-value financial activities for large loans.
What Factors Determine the Interest Rate You Receive?
Lenders consider your credit score, debt-to-income ratio, employment history, loan-to-value ratio, loan term, and the type of loan. Macroeconomic factors — particularly the federal funds rate set by the Federal Reserve — also influence rates broadly. Improving your credit score before applying, making a larger down payment, and comparing multiple lenders are the most effective ways to secure the lowest possible rate.
Frequently asked questions
Is a lower interest rate always better?
Generally yes, but consider the full picture. A lower rate with high fees may be more expensive than a slightly higher rate with no fees, especially for short-term loans. It's worth calculating total cost, including all fees, over the actual time one plans to hold the loan.
How does the Federal Reserve affect interest rates?
The Fed sets the federal funds rate, which influences short-term borrowing costs across the economy. When the Fed raises rates, borrowing becomes more expensive for credit cards, home equity lines, and variable-rate loans. Long-term mortgage rates are also influenced, though they more closely track 10-year Treasury yields.
Keep exploring
Related terms
Fixed Interest Rate
A fixed interest rate stays the same for the entire life of the loan. It provides payment predictability and protects borrowers from rising market interest rates.
Variable Interest Rate
A variable interest rate changes over time based on a benchmark rate like the prime rate or SOFR. It can save money when rates fall but creates payment uncertainty when rates rise.
Principal
Principal is the original amount borrowed on a loan, separate from interest and fees. Reducing principal faster saves significant money over the life of the loan.
Amortization
Amortization is the process of paying off a loan through regular scheduled payments over time. Each payment covers both interest and a portion of the principal balance.
Debt-to-Income Ratio
Your debt-to-income ratio compares your monthly debt payments to your gross monthly income. Lenders use it to assess whether you can afford to take on more debt.
Loan Refinancing
Refinancing replaces an existing loan with a new one, ideally at a lower interest rate or better terms. It can reduce monthly payments or shorten the loan term.