In games of Warhammer: the Old World, all distances are measured in inches ("), using a ruler or tape measure, and can be measured at any time. Distances between models and all other objects (which can be other models, terrain features and so on) are always measured from the closest point on one base to the closest point on the other base (see diagram below).

For example, if any part of a model's base is within 6" of the base of an enemy model, the two models are said to be within 6" of each other.

Sometimes, units will be mounted on movement trays for ease. Nevertheless, always use the model's base, and not the movement tray, as the reference point when taking your measurements.