Kanban Quantity
Kanban quantity is the number of cards, bins, or containers assigned to a part in a pull system, sized from demand, replenishment lead time, safety stock, and container capacity. It represents circulating inventory per signal needed to absorb variability and replenishment delay. Sizing formula: (demand rate × replenishment lead time + safety stock) ÷ container size.
On a manufacturing line, kanban quantity governs how many containers circulate between a supermarket, line-side point-of-use racks, and the upstream process. The number is set so that as operators consume parts, an empty bin or card triggers replenishment before the downstream operation starves. Sizing must cover the whole loop: consumption at point of use, internal transport time, receiving and put-away, plus planned safety stock for variability. If undersized, refill arrives after the last container empties, causing expedites and line stoppages. In warehousing, the quantity is often executed as a fixed-bin standard; each empty bin or scanned tag creates a replenishment order for the same quantity, linking the signal to a specific SKU and location. ERP-based systems store this as a fixed container size or compute it from average daily demand and lead time. Ultimately, kanban quantity caps authorized circulating inventory and synchronizes replenishment to actual consumption.
Is kanban quantity the same as the number of kanban cards?
In many systems, yes: one card corresponds to one circulating container or bin, so the number of cards equals the number of kanbans for that item.
What variables most strongly affect kanban quantity?
Average demand, replenishment lead time, safety stock or safety factor, and container size are the core inputs; some enterprise systems also include scan delta days, allocation percent, or minimum kanban quantity.
Why do different kanban formulas give different answers?
They model the same replenishment loop with different assumptions about safety stock, containerization, and system behavior. Outputs differ when one formula uses cards, another uses containers, and another adds safety factors or minimum quantities.