When estimating how long an implementation project will take, it is important to have a clear idea of the functionality required. For a small company, planning to only implement the finance modules, the process can take from 1 to 2 months. If yours is a medium-sized company and your project includes core financials, sales, purchasing, and inventory control, the implementation project could take 3 to 5 months. If the project is large and includes core financials, sales, purchasing, inventory control, and manufacturing then the entire Dynamics 365 Business Central Implementation project could take between 6 to 10 months.