Carbon residue is a measure of the amount of coke residue left when a hydrocarbon stream is completely distilled. It is used as an indicator of the asphaltene content of a stream and a predictor of the coke yield when the stream is fed to a coker or FCC.

The two common measures of carbon residue are Ramsbottom (RCR) and Conradson carbon (CCR). Both have units of weight %.

In general, a lower carbon residue is more desirable in a crude.