The purpose of the mulch calculator is to help you figure out how much mulch you need to buy for your mulching project. Mulch is conventionally sold by the yard. When you draw an area on the map it tells you how many yards of mulch are required to cover the area and also gives you some square footage calculations in case that is useful to you. There are some price calculations in there, but it’s really up to you to price shop and get the best deal you can.