What is APR vs interest rate on a loan?

The interest rate is the cost to borrow the principal, expressed as a yearly percentage. The APR (Annual Percentage Rate) is the interest rate plus fees — origination, points, and other lender charges — giving you the true annualized cost of the loan.

Lenders advertise interest rates, but federal law requires them to also disclose the APR. The gap between the two tells you how much fees are adding to your cost. A loan with a 7% interest rate and a 2% origination fee has a higher APR than 7% — the exact APR depends on loan term and when the fee is paid.

Interest rate: what it measures

The interest rate (also called the 'note rate' or 'nominal rate') is the annual cost of borrowing the principal balance, expressed as a percentage. It determines how interest accrues day to day. On a fixed-rate loan it stays constant; on a variable-rate loan it adjusts periodically based on a benchmark index (like SOFR or the Prime Rate). The interest rate alone does not reflect the total cost of the loan.

APR: what it measures

The Annual Percentage Rate (APR) is a broader measure of the cost of credit. Under the Truth in Lending Act (TILA), it must include the interest rate plus certain fees — origination charges, discount points, mortgage broker fees, and other prepaid finance charges. The APR is calculated by spreading those fees across the life of the loan and annualizing the total cost, giving you a single comparable number. Two loans with the same interest rate but different fee structures will have different APRs.

When to use each number

Use the interest rate to calculate your monthly payment (principal × rate / 12, adjusted for amortization).
Use the APR to compare total cost across lenders — it's the closest thing to an apples-to-apples number when fees differ.
Watch the APR gap: A 0.25% lower interest rate paired with a 3% origination fee can cost more than a slightly higher rate with zero origination — APR reveals this.
Short loans amplify fees: A 2% origination fee spread over 3 years hits APR much harder than the same fee spread over 30 years.

APR limitations to know

APR is a standardized calculation, but it has limits. It assumes you hold the loan to full maturity — if you refinance or sell before payoff, the actual cost per year changes. For adjustable-rate mortgages, the disclosed APR is based on the initial rate and scheduled adjustments, which may not reflect actual future rates. For business products like merchant cash advances, APR may not be disclosed at all (no TILA requirement for commercial loans) — which is why factor rate to APR conversion matters in that context.

What the authorities say

The CFPB states that the APR is the interest rate plus any additional fees charged by the lender, and advises consumers to compare APRs to APRs — not APRs to interest rates — when shopping loans of the same type. — CFPB — Loan Interest Rate vs. APR
The CFPB explains that for mortgages specifically, the APR reflects the interest rate plus points, mortgage broker fees, and certain other charges — making the APR higher than the note rate whenever upfront fees exist. — CFPB — Mortgage Interest Rate vs. APR
The Federal Reserve's consumer materials note that Truth in Lending Act (TILA) disclosures — including the APR — exist specifically so borrowers can compare the true cost of credit across lenders on a standardized basis. — Federal Reserve — Truth in Lending Overview

Key takeaways

The interest rate is the base annual cost of borrowing principal — it drives your monthly payment calculation.
APR = interest rate + fees (origination, points, etc.), annualized — it reflects total cost of credit.
Always compare APRs when shopping; lenders must disclose APR under the Truth in Lending Act.
A lower interest rate doesn't guarantee a lower-cost loan if fees are higher — APR settles the comparison.
APR assumes full loan term; early payoff or refinancing changes the actual annualized cost.
Related: APR vs interest rate — the real cost of borrowing | Factor rate to APR — the real cost of MCAs and RBFs