Also known as:
A crack spread a measure of refining market conditions based on the difference in price between a refined product and a specific crude grade.
It is used as a rough indicator of the margin from processing light sweet crude through a cracking configuration refinery.
Typically a crack is defined in terms of one specific product versus one specific crude. For example the diesel crack on Brent. In this case it is meant to indicate how much the price of the individual product is contributing to refining profitability.
Some more complicated cracks are used to provide a somewhat more accurate indicator of overall refining margin:
3-2-1 crack - defined as (2 x gasoline price + 1 x diesel price) - (3 x crude price).
6-3-2-1 crack - defined as (3 x gasoline price + 2 x diesel price + 1 x fuel oil price) - (6 x crude price)