Operations Management and Strategic Management · Lean Operations and JIT
Kanban and Pull Production System Explained
Updated 10 October 2026 · Fact-checked
Kanban is a card-based signalling system used in Just-in-Time manufacturing. In a pull system, a downstream process uses a card to ask the upstream process for parts, so work starts only when there is real demand. You solve questions by tracing card flow and applying the kanban count formula.
Understand Kanban and Pull Production System
A push system makes products according to a forecast or schedule. Each stage produces and pushes output to the next stage, whether the next stage needs it or not. If the forecast is wrong, stock piles up between stages.
A pull system works the other way round. The final stage (customer demand or final assembly) triggers production. Each stage makes only what the next stage has used. Nothing is made without a signal. This keeps work-in-progress low and exposes problems quickly, which is why it is central to Just-in-Time (JIT).
Kanban is a Japanese word for "card" or "signboard". It is the signal that carries the pull. A card is attached to a container of parts. When the container is emptied, the card goes back to the upstream stage as authority to make or send one more container. No card, no production.
There are two main types. A withdrawal (conveyance) kanban authorises the movement of a container from the upstream stock point to the user stage. It shows the part, the quantity per container, and where it goes. A production kanban authorises the upstream stage to make a container of that part to replace what was taken. Some books also mention a supplier kanban, used to pull material from outside vendors.
The cards are only the tool. The system works because of discipline: small containers, short set-ups, stable schedules and good quality. Kanban is best suited to repetitive, high-volume production with steady demand. It fits poorly where demand is erratic or products are made to unique orders.
Key rules to remember
- Number of kanbans (containers)
- N = D × L × (1 + S) ÷ C
- D = demand per unit time, L = lead time (same time unit as D) to replenish a container, S = safety factor as a fraction, C = quantity per container. Round N up to a whole number.
- Demand during lead time
- D × L
- Parts consumed while a container is being replenished. Use it to check the formula in steps.
- Rule: no defective parts passed on
- Only good parts go to the next process
- A defect must be stopped at source, otherwise the pull chain breaks.
- Rule: downstream pulls
- Later process withdraws only what it needs, when it needs it
- Upstream never pushes extra parts.
- Rule: upstream produces only what was withdrawn
- Produce quantity = quantity withdrawn
- Production never exceeds the number of cards received.
- Rule: smooth production and fewer cards
- Level the schedule and reduce the number of kanbans over time
- Fewer cards means less stock and shows hidden problems.
How to solve Kanban and Pull Production System questions
Use this method for both theory and numerical questions on Kanban and pull systems.
- 1Read the question and decide the type: definition, types of card, rules, push vs pull comparison, or a kanban count calculation.
- 2For theory, start with a one-line definition of the pull system and say that the card is the signal triggered by actual consumption.
- 3Name the card types: production kanban (make) and withdrawal kanban (move), and add the supplier kanban if the question mentions vendors.
- 4For a comparison, write point by point: trigger, inventory, production basis, flow control, flexibility and suitable situations. Use a table-style list with push on one side and pull on the other.
- 5For a numerical question, list D, L, C and S. Convert D and L to the same time unit before multiplying.
- 6Apply N = D × L × (1 + S) ÷ C. Round up to a whole number of containers and state the unit.
- 7Close with one line of interpretation: fewer kanbans means lower WIP, but too few risks stock-outs.
Quickest way: Kanban count in under two minutes
When to use it: Use in MCQs and short numerical parts where demand, lead time, container size and safety factor are given.
- Make time units match first. If demand is per hour and lead time is in minutes, convert.
- Find demand during lead time: D × L.
- Multiply by (1 + S). If no safety stock is given, use 1.
- Divide by container size C.
- Round up. Never round down, because a fraction of a card does not exist and rounding down causes shortage.
Common mistakes in Kanban and Pull Production System
Calling kanban itself the pull system, or the same as JIT.
The three terms appear together in notes and look alike.
Fix: Say: JIT is the philosophy, pull is the way of controlling flow, and kanban is the card tool that carries the pull signal.
Mixing up production kanban and withdrawal kanban.
Both cards travel with containers and both involve the same part.
Fix: Production kanban = authority to make. Withdrawal kanban = authority to move. Think: make versus move.
Mismatched time units in the kanban formula.
Demand is given per day and lead time in hours, and students multiply directly.
Fix: Convert both to the same unit before computing D × L.
Rounding the number of kanbans down.
Students round to the nearest value out of habit.
Fix: Always round up to the next whole container.
Writing that push systems never use demand information.
Overstating the contrast.
Fix: Say push is driven mainly by forecasts and schedules, while pull is driven by actual consumption downstream.
Claiming kanban suits every type of production.
It is taught as a model technique.
Fix: State that it works best in repetitive, stable, high-volume production, not in one-off or highly erratic demand.
Worked examples
Example 1
A component is used at 240 units per hour in an assembly line. A container holds 60 units. The time to replenish one container is 30 minutes. The safety factor is 10%. Calculate the number of kanbans required.
Show the solution
- Convert lead time to hours: 30 minutes = 0.5 hour.
- Demand during lead time = 240 × 0.5 = 120 units.
- Add safety factor: 120 × 1.10 = 132 units.
- Divide by container size: 132 ÷ 60 = 2.2.
- Round up to a whole number: 3.
Answer: 3 kanbans (containers) are required.
Example 2
Distinguish between a push system and a pull system of production.
Show the solution
- Trigger: push is triggered by forecasts and the production schedule; pull is triggered by actual consumption at the next stage.
- Production basis: in push, each stage makes as per plan and pushes output forward; in pull, a stage makes only what the next stage has withdrawn.
- Inventory: push tends to build work-in-progress between stages; pull keeps it low and limited by the number of cards.
- Control tool: push is typically planned through MRP-type schedules; pull uses signals such as kanban cards.
- Problem visibility: in push, problems are hidden by buffer stock; in pull, low stock exposes problems quickly.
- Suitability: push suits long lead times and uncertain supply; pull suits repetitive, stable, high-volume production.
Answer: A push system produces to a forecast and moves output forward regardless of need, while a pull system produces only on a downstream signal such as a kanban card, giving lower inventory and faster problem detection.
Exam tips
- For a 14-mark theory question, combine kanban types, rules and push vs pull, and present each as a short heading with bullets.
- In MCQs, watch the verbs: production kanban makes, withdrawal kanban moves.
- For the numerical, always show D × L before dividing by C. Step marks are given even if rounding goes wrong.
- Link kanban to JIT in your opening line. Examiners expect it.
- Add one balanced line on limits: needs stable demand and reliable suppliers.
Practice questions from Lean Operations and JIT
- A manufacturer of auto components in Pune moves from a push system to JIT. Which of the following changes is most consistent with JIT purcha…
- A Pune auto-component plant makes batches far larger than customer orders need, so finished goods pile up in the warehouse. Which category o…
- Which of the following is a standard rule for operating a Kanban system effectively?
- In a Just-in-Time (JIT) production system, which of the following best describes the primary objective of the approach?
- Which of the following is generally identified as the eighth waste, added to the original seven wastes of the Toyota Production System?
Kanban and Pull Production System in other exams
The same ground in other exams, if you are preparing for more than one or want another angle on it.
Kanban and Pull Production System: frequently asked questions
What is kanban in JIT?
Kanban is a card-based signalling method used in JIT. A card tells an upstream process to make or supply parts only after the downstream process has used them. It keeps inventory low and ties production to actual demand.
What are the types of kanban cards?
The two main types are the production kanban, which authorises making a container of parts, and the withdrawal (conveyance) kanban, which authorises moving a container to the user stage. A supplier kanban is sometimes added for outside vendors.
What is the main difference between push and pull systems?
A push system produces to a forecast and sends output ahead whether it is needed or not. A pull system produces only when the next stage signals a need, so stock stays lower.
Can the number of kanbans be a fraction?
No. Cards and containers are whole units, so you round the calculated figure up to the next whole number.