![Nearly $1bn already spent on US military campaign against ISIS Nearly $1bn already spent on US military campaign against ISIS](https://mtic.us/wp-content/uploads/2014/09/estimate-cost-isis-war.si_-310x168.jpg)
The US-led military operation against the Islamic State (IS, formerly ISIS) militants has likely so far cost between $780 and $930 million, according to an estimate by Washington-based think tank specializing in defense issues.
The estimate is part of a report attempting to forecast how much the operation might cost in the future.