Kanban Card Template & Replenishment Rules

Purpose

Use this kanban card template and rules to implement a simple pull replenishment for critical components or finished-goods buffers. The package includes a printable card layout, a reliable kanban sizing formula with a worked example, clear replenishment behaviors, emergency override steps, risk checks to avoid brittle deployments, and a short pilot plan.

Printable Kanban Card (example layout)

Print or create a physical card with the fields below. Place one card per container/bin or attach to the kanban loop used in your area.

Card Field Definitions (why each matters)

• Part Number / Description: Exact identifier to avoid picking or replenishment errors.
• Container Size: How many units in a replenishment container or tote; used in sizing.
• Kanban Quantity: Number of containers represented by the kanban loop (calculated below).
• Reorder Point / Trigger: The physical signal that starts replenishment (commonly 'empty container removed' or 'card placed in pickup bin').
• Supplier / Source: Where the replenishment comes from — internal work cell, supermarket, external supplier.
• Lead Time: Time from signal to delivered replacement (use operating days consistent with the process).
• Owner / Responsible: The person or role who manages kanban integrity (not necessarily the supplier).

Kanban sizing formula

Calculate the number of kanban containers required to cover demand during lead time plus a safety allowance:

Number of Kanbans = ceil( (D × L + SS) / C )

Where:

• D = average demand per day (units/day)
• L = replenishment lead time (days)
• SS = safety stock (units) to cover variability (see guidance below)
• C = container size (units per container)
• ceil() = round up to the next whole container (you can’t have a fraction of a physical container)

Worked example

Assume:

• D = 20 units/day
• L = 5 days
• SS = 20 units
• C = 10 units/container

Demand during lead time = D × L = 20 × 5 = 100 units. Add safety stock: 100 + 20 = 120 units. Divide by container size: 120 / 10 = 12. So set Kanban Quantity = 12 containers. That means there should be 12 physical containers (or cards) in the loop.

How to choose safety stock (SS)

Safety stock should reflect demand and lead-time variability plus acceptable stockout risk. For a simple first pilot, use a small fixed buffer (for example, 1–2 days of average demand) rather than a large percentage. Example quick default: SS = D × 1 (one day of demand). Adjust after observing variability.

Replenishment rules (clear, actionable)

1. Signal: A kanban signal occurs when a container is emptied or the kanban card is placed in the pickup bin. The card must be visible and distinct.
2. Pickup / Transfer: The replenishment owner collects the kanban from pickup bin within agreed time (e.g., same shift).
3. Issue / Move: When a refill is issued, the kanban card is returned to the back of the loop (or marked as 'issued') so the count of outstanding kanbans remains correct.
4. Maximum outstanding kanbans: Set equal to the calculated Number of Kanbans above. Do not exceed this number unless using an explicit emergency override.
5. Emergency override: If a sign of impending stockout appears (unexpected surge, supplier failure), follow this process:
   1. Owner evaluates and flags emergency on the card (use an emergency color or sticker).
   2. Notify supervisor and procurement/supplier immediately with part number, current on-hand, and required quantity.
   3. Temporarily increase kanban count only with authorization and document reason and expected duration.
   4. Schedule a root-cause and corrective action review within 48 hours.
6. Accountability: Assign a local owner (role) responsible for weekly kanban integrity checks and a contact at the supplier or upstream process.
7. Review cadence: Recalculate kanban sizing at a regular cadence (monthly during pilot, then quarterly) or when demand/lead time changes by more than ~20%.

Common operational checks (quick risk checks before go-live)

• Is container size consistent and counted accurately? Mismatched containers hide true inventory.
• Are lead times measured in consistent units (operating days) and representative of typical performance?
• Is demand stable enough for kanban? High intermittent spikes require larger buffers or alternate controls.
• Is there a committed upstream owner and reliable supplier process to refill within lead time?
• Are there fail-safe processes for card loss, misplacement, or damaged cards?
• Are multiple systems (spreadsheets, ERP) competing with physical kanban? Align a single source of truth for replenishment rules.

Pilot plan (recommended)

1. Pick 3–7 high-usage, repeatable items with moderate variability (avoid the most volatile or the slowest movers in the first pilot).
2. Collect baseline metrics for 2–4 weeks: average daily demand, current inventory days, stockout incidents, on-time fulfillment from supplier.
3. Print cards and attach to containers. Train owners and operators on the signal and pickup rules (short job-aid: 1 page).
4. Deploy for a minimum of 4–6 weeks. Track the following metrics weekly (see next section).
5. At the end of the pilot, review performance, adjust SS and lead-time assumptions, and decide whether to expand or refine rules.

Metrics to monitor

• Stockouts (events): number of times a kanban failed to deliver before demand required it.
• On-time replenishment: percent of replenishments delivered within agreed lead time.
• Inventory days of supply: average on-hand inventory in days for kanban items.
• Kanban turnover: how many times per period containers are cycled.
• Supplier churn / emergency increases: number of times kanban count increased due to supplier issues.

Common mistakes and how to avoid them

• Using kanban to hide variability: address underlying variability (process improvements, supplier performance) before adding more kanbans.
• Poorly measured lead times: measure real end-to-end refill time, including queueing and weekend/holiday delays.
• Large mixed container sizes: standardize container sizes where practical, or calculate per-container kanbans properly.
• No owner or weekly checks: assign a responsible role and a short checklist to keep the system honest.

Next steps & adaptation

After a successful pilot, create a small kanban playbook for operators and supervisors that includes the printable card, a one-page job aid describing the replenishment flow, contact points for suppliers, and the review cadence. Consider packaging high-use items into a reusable kit for other lines.