For someone with an Economics/Engineering background, how long will it take to prepare for a CMA (Certified Management Accountant) exam? To prepare for the CMA(USA) exam, you need to acquire great knowledge about costing, finance, accounting and strategy. Though it sound difficult but the mentioned areas can be expertised in a period of 6 to 9 months if you have good knowledge of mathematics since there is lots of analysis and calculations to be done. The other portions are simple being theoretical and takes about the same amount of time for both commerce or non commerce background.
Over the years of my handling the subject, I have observed students with good mathematics (presuming you have good knowledge of basic mathematics of class 10 to 12) background being able to grasp the concepts much faster compared to non maths students. Your economics background would also help you but only for a particular topic covering around 5 to 8 percent of the total weightage. Given your background, It would take between 6 to 9 months time for you to prepare for the examination.