Before you start
WBS Checker
Check a work breakdown structure before anything is estimated or scheduled from it: every code once and in order, every parent the exact sum of its parts, and every work package owned and small enough to manage.
Open the WBS spreadsheet: one row per element with a code (1, 1.1, 1.1.1), indented names or a level column, and whatever you keep against each: hours, cost, owner, duration. It is read inside your browser; nothing is uploaded.
Work breakdown structure
Drop a spreadsheet here
One row per element: a WBS code (1, 1.1, 1.1.1) or indented names, and whatever you keep against each: hours, cost, owner, duration.
A structure, not a list
A work breakdown structure is the scope cut into pieces small enough to estimate, assign and track. The drawing tools make the boxes; nothing checks the arithmetic. Codes get skipped when an element is deleted and repeated when one is copied, subtotals typed by hand drift from their parts, and a work package big enough to hide a month of trouble looks the same on the page as one that takes a day.
The 100% rule, as arithmetic
The rule every WBS guide starts with: a parent is exactly the sum of its children, no more and no less. More means work nobody has broken down; less means work counted twice or sitting outside the scope. With hours or costs in the file, this is a sum, and the page checks it on every parent. One wrong subtotal is reported where it is, not again at each level above it. And if the parent rows carry totals, the page says what anyone adding up the whole column will get, because that number counts the work more than once.
Codes and structure
Codes used twice, numbering that skips (1.5.1 then 1.5.3), elements whose parent code is missing, elements listed above their parent, and indentation that disagrees with the codes. A file without codes is read from its indentation or a level column instead, and the clean outline gives every element a fresh code in order.
Work packages
The elements with nothing below them are where work is done and progress is measured. Each needs an owner. The common guide is 8 to 80 hours, and no longer than one reporting period, so progress shows before it is late; both limits are shown and can be changed. A parent broken into a single child, the same name listed twice under one parent, and packages named as actions rather than deliverables are pointed out as well.
What this does not do
It checks how the breakdown is built, not whether the scope is complete: it cannot know a deliverable is missing if nobody wrote it down. It does not draw the WBS as a chart; the clean outline downloads as a spreadsheet that any drawing or scheduling tool can import.