This guide covers everything you need to know about the resource breakdown structure in PMBOK 8. The resource breakdown structure (RBS) is a hierarchical representation of resources organized by category and type — it provides the classification framework for all project resources and supports resource planning, cost estimation, and reporting.
What Is the Resource Breakdown Structure?
The resource breakdown structure is a hierarchical chart that organizes all project resources into categories and subcategories, similar to how the WBS organizes project scope. At the top level, resources are typically divided into major categories: human resources, equipment, materials, and facilities. Each category is then subdivided into specific resource types, enabling systematic planning and tracking at any level of detail.
The RBS serves as the common resource taxonomy for the project. When estimating resources for WBS activities, when reporting resource utilization, or when analyzing resource conflicts, the RBS provides the consistent classification structure that makes these activities coherent and comparable.
On simple projects, the RBS may have just two levels (category and individual resource). On large or complex projects, it may have four or five levels — enabling detailed resource analysis by department, skill type, grade level, or supplier category.
Resource Breakdown Structure in PMBOK 8 — Domain and Process
In the PMBOK Guide 8th Edition, the resource breakdown structure belongs to the Resources Performance Domain and is produced during the Plan Resource Management process. The RBS is developed early in planning to establish the resource taxonomy before resource estimation and acquisition activities begin.
The RBS feeds into the resource requirements estimate (categorizing each required resource according to the RBS), the resource management plan (defining how each resource category will be managed), and cost estimation (associating unit costs with RBS categories).
Key Elements of the Resource Breakdown Structure
A well-structured resource breakdown structure typically includes:
- Level 1 — Resource Categories — Human Resources, Equipment, Materials, Facilities, Services
- Level 2 — Resource Types — subcategories within each category (e.g., Internal Staff, Contractors, Vendors)
- Level 3 — Specific Resources — named individuals, specific equipment items, or specific material types
- RBS Codes — alphanumeric identifiers for each RBS element to support cost coding and reporting
Resource Breakdown Structure Example — Project Phoenix
The Project Phoenix RBS had three levels. At Level 1: Human Resources, Technology Services, and Facilities. Under Human Resources at Level 2: Internal Staff (Alex Morgan, Sam Lee, John Tran, Maria Santos) and External Vendors (BrightFrame Design Studio). Under Technology Services: Hosting and Infrastructure (CloudHost Pro), Software Licenses (GitHub Enterprise, Figma, Adobe CC), and Tools (Google Analytics, Jira). Under Facilities: MCG Conference Room A.
The RBS was used as the cost coding structure for the project budget, with each resource category linked to a cost account code. This enabled Alex to generate cost reports by resource category at any time during the project — confirming, for example, that External Vendor costs were running exactly as planned at $13,200 (BrightFrame’s fixed-price contract), while Internal Staff costs were $400 under plan due to John Tran’s reduced hours being partly offset by Sam Lee’s additional time.
You can download the complete filled-in example below — it shows exactly how the resource breakdown structure was built for a real project.
Download Free Resource Breakdown Structure Template and Example
We have prepared two free resources to help you build a resource breakdown structure for your own projects:
- Download the Resource Breakdown Structure Template — PMBOK 8 (blank, ready to fill in)
- Download the Resource Breakdown Structure Example — Project Phoenix (filled in for a real $72K website launch)
Both are free downloads — no registration required.
Resource Breakdown Structure — Best Practices and Common Mistakes
Align the RBS with the organization’s cost accounting codes wherever possible — this makes financial reporting and project accounting much simpler. Keep the RBS at a consistent level of detail: some projects over-decompose human resources into individual people while leaving equipment at a generic level, creating an imbalanced structure. Use the RBS as the reporting taxonomy from the start so that resource utilization reports are meaningful and comparable across projects.
The resource breakdown structure is most effective when it is developed at the start of planning and used consistently throughout the project for resource estimation, assignment, and cost tracking. Teams that skip or rush this structure often find their resource data fragmented and difficult to aggregate for management reporting.
Want to master project management with PMBOK 8? The PMBOK Guide 8th Edition is the definitive reference. Get your copy and use it alongside these free resources.
Free Template & Filled-In Example
Apply what you’ve learned with these two free resources:
- Download the Free Resource Breakdown Structure Template (PMBOK 8) — Ready-to-use blank template for your next project.
- Download the Filled-In Example — Project Phoenix — See exactly how this document was completed for a real $72K website launch project.
Project Management