It varies per strain, but normally from the time flowering is induced it will take about 2 months, give or take a couple weeks. In general it is the plants particular photo period that determines how long it will take. It also depends on nutrients, lighting, humidity, and other stuff. If there's a lot of light, and everything is perfect, grow times can be reduced. I've heard of some taking over 3 1/2 months, but that's kind of unusual.

The amount of time a plant spends before flowering is induced varies widely. It depends on available space and stuff. You can veg a plant for 10 years in a warehouse and end up with a truckload of buds, or you can veg for 2 weeks and end up with a half ounce.