Blending hydrocarbons with varying gravities or molecular structures can result in a phenomenon known as shrinkage. In the same way that mixing 1 gallon of golf balls and 1 gallon of sand results in a mixture of less than 2 gallons, mixing crudes often results in a decrease in expected volume. This calculator uses methods descibed in the Manual of Petroleum Measurement Standards - Chapter 12 - Section 3 (API 12.3).
This calculator works on an iterative method to calculate, in each step, the amount of diluent that would be required to reach a target density and then determine any discrepancies caused by shrinkage. Further iterations can then be used to get closer to the target density. Iterations continue until the density of the blend is within 0.0001% error with the target density (however, only a maximum of six iterations will be shown in the table).
This calculator has been provided as a tool, and should be used solely for informational purposes. It is not intended to replace your own calculations as each situation requires specialized considerations. Crude Quality Inc. accepts no responsibility for any inconsistencies with the actual chemistry that may arise from the use of this calculator.