What is a variable APR on a credit card?

A variable APR moves up or down with a benchmark rate — usually the U.S. Prime Rate. When the Federal Reserve raises or lowers its benchmark, Prime follows, and your card's APR follows within one to two billing cycles.

Nearly all consumer cards carry a variable APR expressed as a formula in your agreement: Prime Rate plus a margin. The margin is set by the issuer from your creditworthiness at approval and usually stays fixed; what moves is Prime, which banks reset in lockstep with the Fed. Example: if your agreement says Prime + 14.99% and Prime is 8.50%, your APR is 23.49%; a half-point Fed cut drops it to 22.99% with no action on your part. It only matters if you carry a balance — pay in full and you never pay interest regardless of where rates move. Issuers must notify you of a rate change, but not for a variable rate simply tracking its benchmark, since that movement is already disclosed.

Reviewed by the ClearValue Editorial Team · Last updated 7/8/2026