Applies To
	Product(s):	STAAD.Pro
	Version(s):	All
	Environment:	N/A
	Area:	Steel Design
	Subarea:	General Steel Design Solutions
	Original Author:	Bentley Technical Support Group

The KL/r value that STAAD reports for the Y axis for a single angle does not match what I get from my hand calculation. Can you explain why? 

For single angles, the local Y and Z axes are the principal axes as shown below:

 

The KL/r value is computed using ry and rz which are based on the principal axis system. Chances are that your handculation uses the geometric axes.