You can use the AutoLISP function......TEXTBOX
Definition:
Measures a specified text object, and returns the diagonal coordinates of a box that encloses the text
(textbox elist)
Argument:
elist
An entity definition list defining a text object, in the
format returned by entget.
If fields that define text parameters other than the text
itself are omitted from elist, the current (or default)
settings are used.
The minimum list accepted by textbox is that of the
text itself.
