WBS in Project Management: The Ultimate Guide to Understanding WBS

Managing large or complex projects can be challenging. With an array of tasks to complete, keeping track of their dependencies can become all-consuming. That's where WBS project management can help.

What is WBS?

WBS stands for Work Breakdown Structure. It is a project management method that uses visual, hierarchical diagrams to break down projects into discrete steps or tasks. The process enables project managers to start with the end date and work backward to determine a start date.

The top task of the diagram is the deliverable. Subsequent levels subdivide the project into subtasks necessary to complete the project. Resources, costs, and times are associated with each task or subtask to help manage the overall project costs and timelines.

How to use WBS in project management

WBS is like an outline for projects. When creating a writing or speaking outline, you identify the key points and list supporting information under each point. For example, an outline for a speech or document might look like the following:

A.  Level 1

     A.1. Level 2

           A.1.1. Level 3

               A.1.1.1 Level 4

            A.1.2 Level 3

     A.2 Level 2

The process continues until the entire speech or document is outlined.

Setting up a WBS

WBS uses the outline basics and adds information on resources, start and end dates, and dependencies. Although project managers can implement WBS manually, most use software designed to make the process faster to complete and easier to modify.

  • Step 1. Deconstruct the project into Level 1 elements. These are discrete work elements that must be completed before the project is considered finished. They are the A, B, C levels in an outline. The number of Level 1 elements varies, but they must represent 100% of the project requirements.
  • Step 2. Break down Level 1 elements into lower-level tasks. These are the A.1, A.2 entries in an outline. Again the number of these Level 2 entries may vary, but they must represent 100% of the tasks needed to complete the Level 1 element.
  • Step 3. Decompose Level 2 elements. These would be the same as A.1.1 and A.1.2 entries in an outline.
  • Step 4. Continue to break down the tasks until each task can be assigned to a single entity, whether it is an individual or a team. Be careful not to add more tasks than necessary. Their purpose is to make the project more manageable, not more complex.

Setting up WBS tasks

Most WBS software automatically assigns task numbers based on a WBS hierarchy. Every task needs a unique number for identification and tracking. Along with the number is a description or name. For example, a task name might be "Concatenate Transaction Files." The name may mean something to the programmer assigned to the task, but it doesn't provide details that others might need. Task descriptions provide that clarity and are often placed in a WBS document. Some software packages allow notes to be associated with each task, so added details can be provided as part of the WBS.

After numbering, naming, and describing each task, project managers identify the entities responsible for completing the task. With team-assigned tasks, the team leader is considered the task owner. Other information to include in a WBS project includes:

  • Task Dependency. Tasks often depend on other tasks. For example, you can't frame a house before the foundation is laid. WBS allows managers to create the dependencies, indicating that one task must be complete before another task can start.
  • Task Status. Project participants can indicate task statuses such as complete or in-progress. Some WBS include a percentage for in-progress tasks.
  • Task Start and End Dates. Assigning start and end dates to each task results in a project timeline for completion.
  • Task Costs. Calculating the cost on a per-task basis provides a project-level cost estimate.


Using WBS software enables project managers to monitor project status and costs while providing participants with a clear path to completion. As an established project management tool, WBS provides a visual display of project timelines and dependencies. To learn more about WBS and other project management tools, check out our website.

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