not a lot, but it depends entirely on what you feed and the conditions you provide - some folks can start with a pound and in 6 weeks have none left alive!! vermicomposting isn't a very productive way to get a large amount of 'fertilizer' [soil amendment], but a way to process waste into useable plant nutrients

one pound of worms will process about 1/2lb of veg waste per day, and some of that volume 'disappears' in energy and reproduction - the volume of the bin might not appear to grow at all as the weeks go by, but the contents change into the finished product

Bill

It depends on what you want to do with the material. If you want it completly finished it takes many months. If you just want some for your houseplants or yard plants. After 6 months you could easily harvest half of the bin contents to use on your plants. Our worms create a very rich plant source for nutrients and disease prevention. Remember healthy growing plants are less susceptible to disease. I don't worry about how finished it is I just harvest about half to 3\4 of the bin contents and start feeding again. Workls great for me.