About WIP Limits and Card Size

One of the new features just released in LeanKit Kanban is the ability to specify WIP Limits by Card “Size”, instead of the number of Cards in a lane.  Earlier this week, after announcing this feature, I got a couple of “Really?” emails like this one, from Arne Roock:


just saw your new features. Most of them look really great! But one feature confuses me: “WIP Limits by Card Size”

In my understanding we intend to limit the number of items we´re working on – not the number of Story Points etc. So working at 10 items with the size of 1 is completely different from  working at two items of 5 or one item of 10!

Now I´m interested: Have you ever seen teams succeed with limiting the total amount of effort instead of the number of cards?


And of course, he’s entirely correct.  The best way to limit work in process, we believe, is to limit the total number of items you are working on at one time. In our team, we don’t use the Card Size field at all, and whenever possible, we encourage our customers not to use it. The most successful Kanban systems we’ve observed don’t track card size at all, once an item has made it onto the board (though some planning-level sizing may have occurred when deciding how to break down a larger item in to component parts to flow it onto the board).

So, why make this feature available at all? Because our customers wanted it, and because more and more of our customers are using LeanKit for things other than Capital-K Kanban:

  • We have many pure Scrum teams using LeanKit as the visualization method – with no real need to consider themselves “ScrumBan” or to “convert” to using Kanban. Enforcing WIP by Card Size allows these teams to plan their sprint backlog based on Card Size, setting a WIP limit for some “sprint backlog” lane either on the left side of the board or in the main Backlog in LeanKit.
  • We also have many teams outside of Software Development and IT organizations using LeanKit, for academic research projects, sales pipeline visualization, marketing plans, strategy canvases, and more.
  • While many of our customers are using LeanKit at the Team level, we’re getting more and more that are using it to visualize and plan at the portfolio level – an enterprise Kanban view. For planning at this level, some teams would like to be able to allocate  capacity based on size, not just number of items.

So, for those of you who are new to Kanban, and trying to learn how to be successful with it, we definitely recommend limiting your Work in Process by the # of items, not by the size of those items.  But for those of you who are pushing the boundaries in every direction, applying traditional Scrum (funny…when did Scrum become “traditional”?), or applying Kanban outside of IT in other environments where “best practices” aren’t really well understood yet, please feel free to use the new WIP limit by card size feature.

And good luck. 🙂

Chris Hefley

Chris Hefley is a co-founder of LeanKit. After years of coping with “broken” project management systems in software development, Chris helped build LeanKit as a way for teams to become more effective. He believes in building software and systems that make people’s lives better and transform their relationship with work. In 2011, he was nominated for the Lean Systems Society’s Brickell Key Award. Follow Chris on Twitter @indomitablehef.