Actually, according to these two pages ->
http://www.seds.org/billa/twn/antx.html
http://www.astro.uiuc.edu/~kaler/sow/antares.html
Antares is roughly 700 ~ 900 times larger in diameter than the
Sun, and 9 000 ~ 12 000 times more luminous.
Antares A is one of the largest
stars out there, along with
Betelgeuse.