How to create a work breakdown structure and why you should

Whether you’re launching a new product or managing a complex software rollout, the scale of a project can quickly feel overwhelming. That is where the work breakdown structure comes in. A work breakdown structure is the architectural blueprint of project management. It takes a daunting objective and breaks it down into a hierarchy of deliverables. By turning project chaos into an organized roadmap, work breakdown structures ensure your team stays focused and maximize your chances of success.

What is a work breakdown structure?

A work breakdown structure (WBS) diagram starts with a large project or objective and breaks it down into smaller, more manageable pieces that you can reasonably evaluate and assign to teams. Rather than focusing on individual actions required to accomplish a project, a WBS generally focuses on deliverables or concrete, measurable milestones, making them more manageable and quantifiable. These deliverables may also be called work packages, tasks, sub-tasks, or terminal elements. A work breakdown structure highlights the relationships among these elements. It looks something like this.

Why use a WBS in project management?

There are several reasons why breaking down a large project is beneficial. It can help you:

• Estimate the cost of a project
• Establish dependencies
• Determine a project timeline and develop a schedule
• Write a statement of work
• Assign responsibilities and clarify roles
• Track the progress of a project
• Identify risk

All of these benefits essentially arise from working with chunks of a project that you can accurately visualize rather than trying to digest and interpret an overwhelming task in one fell swoop.

How to create a work breakdown structure

1. Define the scope and objectives 

Record the overarching objective you are trying to accomplish. This objective could be anything from developing a new software feature to planning a go-to-market campaign. Document these details in your project charter. This will be your guiding reference.

2. Break it down into key phases and deliverables 

Start dividing the project into phases, large deliverables, or subtasks. Stop before you get to the point of listing out every action that must be taken. Remember to focus on concrete deliverables rather than actions.

3. Organize deliverables into work packages

Break down each deliverable into all the tasks and subtasks required to complete it. Organize the tasks into work packages. Work packages are the lowest level of the breakdown and should define the work, duration, and costs for each task, as well as task owners. Each work package should provide assignments that can be completed within a reporting period. 

Tips for making a work breakdown structure

As you make a work breakdown structure, use the following rules for best results:

• The 100% rule: The work represented by your WBS must include 100% of the work necessary to complete the overarching goal without including any extraneous or unrelated work. 
• Mutual exclusivity: Do not include a subtask twice or account for any amount of work twice. Doing so would violate the 100% rule and lead to miscalculations when determining the resources needed to complete a project.
• Outcomes, not actions: Focus on deliverables and outcomes, not actions. For example, if you were building a bike, a deliverable might be “the braking system” while actions would include “calibrate the brake pads.”
• The 8/80 rule: A work package should take 8-80 hours of effort. Other guiding rules suggest the package shouldn’t take more than 10 days or exceed a standard reporting period. When these benchmarks don’t apply, use your best judgment to keep the task manageable. 
• Three levels: Generally speaking, a WBS should include about three levels of detail. However, some branches of the WBS will be more subdivided than others.
• Make assignments: Every work package should be assigned to a specific team or individual. There should be no overlap in work, so responsibilities are clear.

Work breakdown structure example

As you think about how to make a work breakdown structure, let’s look at an example of building a house.

Notice how the rules of building a WBS are applied in this example: 

1. The house-building project is divided into three main sections: foundation, exterior, and interior. 

2. Those sections are further subdivided into one or two more levels for a maximum of three levels.

3. The effort required to build a house has been allocated across all work packages, totaling 100%. There is no duplication of work represented in this work breakdown structure diagram. 

To further enhance this diagram, you could add the budget for each work package and assign a team to each.

Work breakdown structure formats

When creating a work breakdown structure, you can choose from several different format options, such as a hierarchical table, an outline or numbered list, a tabular view, or a tree diagram. The example above uses a tree format, which is the most visual option. It structures the WBS like an org chart and shows the hierarchy of tasks, providing space for additional information about each work package.

Outline structure

A text outline is the simplest WBS format. It is easy to put together and shows the hierarchy of tasks. However, it is difficult to add additional information about budget, duration, and assignment using this format.

                    Build a House

                         1 Foundation

                              1.1 Excavate

                                   1.1.1 Dig

                                   1.1.2 Level

                              1.2 Frame

                              1.3 Concrete

                                   1.3.1 Pour

                                   1.3.2 Cure

                         2 Exterior

                         3 Interior

Hierarchical structure

This format is less visually intuitive but shows the hierarchy of tasks. Because it is a table, this format fits easily onto a page.

Tabular view

A tabular view is a more visually intuitive way to show hierarchy using a table.

WBS dictionary

A WBS dictionary is formatted like the hierarchical structure, but it includes a brief description of each work package. When documenting a project, a WBS dictionary is often included in addition to a visualization of the WBS. It helps to clarify the scope of each task so that all team members understand their responsibilities.

Work breakdown structure template

To get you started, here are several work breakdown structure templates you can use. Simply click to open the template, and then customize the information, layout, and design.

WBS template for project management

General work breakdown structure template

Detailed work breakdown structure template