Index Rate
Also known as: benchmark rate, reference rate
A publicly published interest rate (such as SOFR or the prime rate) that lenders use as the baseline for setting variable interest rates. A variable-rate loan is priced as 'index rate + margin.' When the index rises, your rate rises with it.
Full definition
An index rate is a standardized, independently published interest rate benchmark that lenders use to price variable-rate loans. The most common indices for consumer loans are: Prime Rate: Published daily by the Wall Street Journal based on the federal funds rate set by the Federal Reserve. Credit cards and some personal loans are priced as 'prime + X%'. When the Fed raises rates, prime rises, and so does your variable loan rate. SOFR (Secured Overnight Financing Rate): The replacement for LIBOR since 2023. Used for variable-rate mortgages, student loans, and some personal loans. Reflects overnight lending rates in Treasury repurchase markets. How variable loan rates are calculated: Lender sets a margin (e.g., +5%) on top of the index. If SOFR is 4.5% and the margin is 5%, your rate is 9.5%. If SOFR rises to 5.5%, your rate becomes 10.5%. Why it matters to borrowers: A 3-year fixed personal loan at 10% is predictable regardless of Fed actions. A variable-rate loan starting at 9% linked to prime could become 12% or 14% if the Fed raises rates during your loan. For personal loans, which have shorter terms than mortgages, the index rate risk is more concentrated. Checking the current index: The prime rate is published at wsj.com/market-data/bonds/moneyrates. SOFR is published by the New York Federal Reserve at newyorkfed.org.
- Written by
- Get Advance Loan Editorial Team
- Reviewed by
- Compliance Review
- Published
- January 15, 2026
- Last reviewed
- June 15, 2026
- APR (Annual Percentage Rate)APR is the yearly cost of borrowing, expressed as a percentage of the loan amount. It includes interest plus most lender fees, so it's a more complete measure of cost than the interest rate alone.
- Interest rateThe interest rate is the percentage of the loan balance charged per year as interest, excluding fees. It is a component of, but smaller than, the APR.
- Fixed interest rateA fixed rate stays the same for the entire life of the loan, so the monthly payment never changes. Most U.S. personal loans are fixed-rate.
- Variable interest rateA variable rate can change over the life of the loan, usually tied to an index like the prime rate. Monthly payment can rise or fall.
- Prime rateThe prime rate is the benchmark interest rate U.S. banks publish for their most creditworthy commercial customers. Many consumer rates are quoted as prime + a margin.
- Loan termThe loan term is how long you have to repay the loan, usually expressed in months. Common personal-loan terms are 24, 36, 48, 60, and 72 months.
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