Flow rate and column load scaling are only required when changing column internal diameters. Scaling up is performed when moving from a small to a large diameter column, for example, analytical to preparative chromatography. Scaling down is performed when moving from a large to a small diameter column, for example, analytical to capillary chomatography. The scaling allows peak retention times to remain relatively constant between different dimension columns.

Assuming column length is a constant, the scale factor can be calculated using the following formula:

$ \textrm{\small{Scale Factor}} = \frac{(\textrm{Column A internal diameter})^2}{(\textrm{Column B internal diameter})^2} $

As an example, the calculated scale factors based on a 4.6 mm internal diameter column are: