What it means
A WBS describes what must be delivered, not when it happens. Each level splits the one above it, and the lowest level, called work packages, is where cost and effort are estimated. Many teams pair it with a WBS dictionary that describes each element. It differs from a task list or schedule, which adds sequence, dependencies and dates to the same work.
Why it matters when you buy software
Project management tools handle a WBS in different ways. Some offer nested tasks and subtasks, some add outline numbering or WBS codes, and some include a dedicated WBS view or chart. Plan tier can limit these features, along with dependencies, Gantt charts and cost fields. Check whether a tool supports several levels of hierarchy and can export the structure before you rely on it for large projects.
How it works in practice
A team starts with the final deliverable, splits it into major deliverables, then splits those again until each work package is small enough to estimate. A website launch, for example, might divide into design, content and development, with page templates and copywriting as work packages beneath them. Teams then add owners, estimates and dates.
See also: Agile, Gantt chart and the glossary index.