The main story of Call of Duty: Modern Warfare 3 lasts around five hours, according to HowLongToBeat. However, you have to be solely focused on the story or just really good to beat it in that time. If you go for some of the achievements as well, then it will take around seven hours.

Modern Warfare 3's campaign should take you roughly 4-7 hours to complete. This is based on our run through the single-player component on Regular difficulty, as well as on community sentiment and reports.