Kanban Calculation: How to Size a Supermarket (Formula and Calculator)
A supermarket only works if its size matches demand and replenishment lead time. Too small, and the downstream process stops. Too large, and the inventory eats up the gains of your future state design.
Kanban calculator
Formula
The classic kanban formula gives the number of cards (containers) in the loop.
Replenishment lead time
Replenishment lead time covers the card return, waiting time in the kanban post, changeover, producing one batch and moving it back to the supermarket. It is the biggest lever: cut changeover time in half and run smaller batches, and the supermarket shrinks by half.
In the editor
The kanban calculator in the toolbar takes daily demand from the settings, calculates cards and inventory, and can write the quantity straight into the selected supermarket. The map checks flag supermarkets that have no pull or kanban connection.
Practice in the editor
Open the future state template and resize the "Stamped parts" supermarket with the kanban calculator.
Open the template in the editor Start blankFrequently asked questions
What safety factor is typical?
10 to 30%, depending on how much demand and uptime vary. Start on the high side and lower it once the loop is stable.
What is the difference between a production kanban and a withdrawal kanban?
The withdrawal kanban authorizes the downstream process to pull material from the supermarket. The production kanban tells the upstream process to make the quantity that was pulled.