An interest rate swap (IRS) in which one leg is tied to some inflation index (consumer price index). It enables the holder to transfer inflation risk to a counterparty in order to match future liabilities. The non-inflation leg of the swap can be a floating rate such as LIBOR. Variants on such a swap include: real rate swap, capital indexed swap, indexed annuity swap, zero coupon swap, etc.

It is also known as a retail price index swap (RPI swap) in the U.K.