How to create kanban cards with QR codes for inventory

There's a reason Toyota invented the kanban system in the 1950s: it works. A physical card that moves with inventory creates visibility that no spreadsheet can match. When you combine kanban cards with QR codes, you get the best of both worlds: visual management and instant digital updates.

Here's how to implement a kanban card system with QR codes in your shop.

What is a kanban card?

A kanban card is a physical signal that triggers action. In inventory management, it typically means "time to reorder." The card sits with your stock, and when you reach the reorder point, the card becomes visible, telling you to place an order.

The beauty of kanban is its simplicity. No checking spreadsheets. No remembering to run reports. The card is right there, attached to the inventory it represents.

How traditional kanban works

1. Attach a kanban card to your inventory at the reorder point (e.g., when you're down to 10 units)
2. As you use inventory, you eventually reach the card
3. Seeing the card triggers a reorder
4. When new stock arrives, the card goes back to the reorder point

This system has managed billions of dollars in manufacturing inventory for decades. It's battle-tested.

Why add QR codes?

Traditional kanban has one weakness: the card is physical, but your ordering and tracking systems are digital. QR codes bridge that gap.

With a QR code on each kanban card, you can:

• Scan to view item details: Pull up the item in your inventory system instantly. See cost, supplier, order history.
• Scan to trigger reorder: One scan can create a purchase order or add the item to a reorder list.
• Scan to update counts: Receiving new stock? Scan and enter the quantity. Done.
• Track from anywhere: Anyone with a phone can scan. No need to be at a specific computer.

Setting up your kanban card system

Step 1: Identify your high-turn items

Start with items that move frequently and cause problems when you run out. For most shops, this is 20% of items that represent 80% of usage. Common candidates:

• Raw materials you use daily
• Fasteners and hardware
• Consumables (cutting tools, abrasives, welding supplies)
• Packaging materials

Step 2: Calculate reorder points

Your reorder point is how low you can go before you need to order. The formula:

Reorder Point = (Daily Usage × Lead Time) + Safety Stock

Example: You use 10 units per day, supplier takes 5 days to deliver, and you want 3 days of safety stock.

Reorder Point = (10 × 5) + (10 × 3) = 80 units

Step 3: Design your cards

A good kanban card includes:

• Item name and code: Clear identification
• Reorder quantity: How much to order
• QR code: Links to the item in your inventory system
• Supplier info: Who to order from
• Storage location: Where this item lives

Step 4: Print and laminate

Kanban cards need to survive shop conditions. Print on card stock and laminate, or use a label printer with durable labels. The QR code must stay scannable.

Step 5: Place cards at reorder points

This is the crucial step. The card needs to become visible exactly when you hit your reorder point. Methods:

• Between containers: Put the card between your last container and the reorder quantity
• Marker in bins: Draw a line or place a divider at the reorder level
• Separate zones: Have a "use first" zone and a "reorder zone" on your shelving

Using QR codes effectively

What the QR code should link to

Your QR code should open a page where users can:

1. See current stock levels
2. View item details (cost, supplier, specifications)
3. Trigger a reorder with one tap
4. Update the quantity after receiving stock

Make scanning frictionless

The easier it is to scan, the more your team will use the system. Tips:

• Position cards where they're easy to scan (not buried under stock)
• Use high-contrast QR codes (black on white works best)
• Test in shop lighting conditions before printing all your cards
• Train your team on the workflow: scan, tap, done

Card sizes and formats

Different situations call for different card sizes:

Full cards (3" × 5" or larger)

Best for:

• Raw materials on shelving
• Large containers or pallets
• Items that need detailed info visible

Labels (1" × 2" to 2" × 3")

Best for:

• Bins of small parts
• Drawer systems
• High-density storage

Hanging tags

Best for:

• Items on hooks or pegs
• Tools and equipment
• Items that move around the shop

Common mistakes to avoid

Setting reorder points too low

If you're constantly running out before orders arrive, your reorder points are too aggressive. Add more safety stock or reorder sooner.

Not training the team

A kanban system only works if everyone knows how it works. Make sure your team understands: see the card, scan the code, take action.

Ignoring the cards

If cards pile up without action, the system breaks down. Make sure there's a clear process for who handles reorders and how quickly.

Making QR codes too small

A QR code that won't scan is useless. Test your cards before mass printing. Generally, QR codes should be at least 0.75" square for reliable scanning.

The payoff

Shops that implement kanban with QR codes typically see:

• Fewer stockouts: Visual triggers catch low inventory before it becomes a crisis
• Less time on inventory: No more walking around checking levels
• Better data: Every scan updates your digital records
• Empowered team: Anyone can scan and trigger a reorder

The kanban system has been proven in manufacturing for 70+ years. QR codes make it faster and connect it to your digital systems. Together, they create an inventory management approach that's both simple and powerful.

Ready to implement kanban in your shop? See how AirShop makes it easy.