What is a Data Flow Diagram | Lucidchart A data flow diagram can dive into progressively more detail by using levels and layers, zeroing in on a particular piece. DFD levels are numbered 0, 1 or 2, and occasionally go to even Level 3 or beyond. A Beginner's Guide to Data Flow Diagrams - blogpot The Different Levels of DFDs and the Context level Data Flow Diagram. DFDs can range from simple overviews to complex, granular representations of a system or process with multiple levels, numbered from 0 to beyond. But the most common and intuitive DFDs are Level 0 DFDs, which are called context diagrams.