Base Theory of Kanban Calculation

The number of Kanban you need to have in the circuit between downstream and upstream is a simple calculation. It works both for "production" and "move" Kanban.

Number of Kanban = [ DD * LT * (1 + % SS) ] / Q

DD =Daily Demand

LT = Lead Time (in Days)

SS = Safety Stock

Q = Quantity in a Container

Example:

Let us imagine a downstream process that uses 100 tapes/day (on average).
The lead time to obtain new tapes once the signal start from the Point of Use (POU), arrive to the upstream (or supplier) and the tapes are delivered to the POU is 5 days.
The Safety Stock in percentage is 20% (to compensate demand variation or delays)
Every container is of 50 tapes.

N° of Kanban = 100 * 5 * 1,20 / 50 = 12 Kanban

What does it means?
It means that in the "circuit" between upstream and downstream 12 Kanban (Tags, Container or other form of Kanban) has to be present.

Points of attention.
The demand and lead time has to be with the same time base (Days, Hours, Minutes).
The Number of Kanban has to be rounded up to the integer