Media analyst Rich Greenfield of Pali Research today writes (registration required) that his prediction for Monsters vs. Aliens’ worldwide box office estimate of $483M is “conservative ($186 domestic, $297 international), given the recent strength in domestic movie attendance trends (consumers escaping from the gloomy economy) and the benefit the movie should see from premium 3-D” pricing. He also calculates exactly the upcharge for the DreamWorks Animation’s toon. On DWA’s year end conference call back in February, Jeffrey Katzenberg thought it would be in the “meaningful” $5 range for the domestic market. Greenfield says it’s around $3.18.

“If attendance is weighted toward premium priced 3-D screens, we suspect the box office outperformance (vs. a standard 2-D film with the same total attendance) of at least mid-teens if not higher. In turn, this appears to imply that our opening weekend forecast is conservative.

“We are currently assuming Monsters vs. Aliens opens at $55M, which is 13% below where Madagascar 2 opened in November 2008, however, adjusted for higher (3-D) ticket pricing, implied attendance levels would be nearly 25% lower (while this is an original film vs. a sequel, downside risk at $55M opening weekend appears limited).”