If your plan is to build a concrete block wall, make sure to use this concrete block calculator before you lay the first stone! Is the question, "How many concrete blocks do I need for this project?", on your mind? If so, this tool will surely be of great help to you. You can use it to find out how many cinder blocks are needed for a wall of a particular size, estimate the required amount of mortar, and also get an idea of how much the materials needed for your project will cost, based on the average concrete blocks cost.