Aug 18 (Reuters) - Chip tools maker Applied Materials Inc forecast fourth-quarter revenue above market estimates on Thursday as semiconductor producers scale up output to plug a supply shortage that has hobbled sectors across the economy.

The company forecast revenue of $6.65 billion, plus or minus $400 million, compared with analysts' average estimate of $6.57 billion, according to Refinitiv IBES data.

(Reporting by Chavi Mehta and Tiyashi Datta in Bengaluru; Editing by Aditya Soni)