Disclosed are a method and a system for determining threshold voltage (Vt) variations in field effect transistors (FETs), wherein multiple field effect transistors (FETs) (e.g., at least a first FET and a second FET), which are similar in design except for having different effective channel widths, can be selected for processing. Information regarding these multiple FETs (e.g., the ratio of the different effective channel widths and other information) can be acquired and used to define the relation between a standard deviation of an uncorrelated Vt variation and a difference between a first average Vt associated with the first FET and a second average Vt associated with the second FET. The relation can, depending upon the FET layouts, be used for different purposes (e.g., for characterizing the threshold voltage mismatch between a pair of adjacent essentially identical FETs on a chip or for characterizing a width scaling relation).