Scope and Quality · tool 1 of 9
Work Breakdown Structure (WBS)
Work Breakdown Structure (WBS): breaks the total scope into small, manageable pieces of work that can be estimated and owned.
Best for: Planning the scope · Time: 2–4 hours
Domain: Scope · Focus area: Planning
How it works
A hierarchical tree: the final deliverable at the top, broken into major deliverables, then into work packages — the smallest unit you can estimate, assign to one owner and track.
- 100% rule: the children of each box add up to exactly 100% of the parent — nothing missing, nothing extra.
- Describe deliverables (nouns), not activities (verbs).
- Stop splitting when a package takes roughly 1–10 days of effort.
How to apply it
- Write the final deliverable in the top box.
- Split it into 3–7 major deliverables or phases, with the team in the room.
- Keep breaking down each branch until every package can be estimated and given to one owner.
- Number every box (1.1, 1.2.3…) and reuse those numbers in your schedule, budget and RACI.
Website launch → 1 Design, 2 Content, 3 Build, 4 Launch → 3.1 Front-end, 3.2 Back-end…
Use sticky notes on a wall first. It’s faster to move paper than to restructure a file — and the team owns what it builds.
Use it
- Template: WBS Dictionary (blank), filled example
Quick check
What does the 100% rule say?
Sources
- PMBOK® Guide, 8th edition, and The Standard for Project Management (PMI, 2025)
Last reviewed 2026-11-02 against the PMBOK® Guide, 8th edition · Practitioner review pending · How this guide is made