Using Barcodes to Reduce E-Commerce Picking Errors


If you resell large quantities of kitchen scales over the Internet then the best thing that you can do is to let Amazon or a similar organization handle the picking, packing and shipping of your products. But what if you are one of the myriad of small E-Commerce organizations that sell custom or semi-custom products such as:

  • T-Shirts in many different colors and sizes with custom graphics silk-screened onto the T-shirts.
  • Kits of medical supplies, tailored to the needs of individual patients, and shipped on a regular basis.
  • Delivery of meals made to order or kits of food shipped to home chefs
  • Kits of fishing lures tailored to the needs of each customer.

then the situation becomes much more complicated.

In each of these, and many similar cases, each order is different and is not easy to restock (unlike boxes of kitchen scales). So it is important to get the order right in the first place.

Each of these cases is critically dependent on picking the correct materials in response to each customer's order.

While an organization such as Amazon can afford to use advanced techniques such as picking robots, pick to sound or light, and wave picking, these are typically out of reach of the smaller E-Commerce organizations in terms of cost and complexity. In this article, we look at how to use barcodes to dramatically improve kit picking accuracy without spending a lot of money or time on systems maintenance.


Pick Orders

In order to correctly pick the correct materials for an order, we start with the customer's order which will probably have come from an E-Commerce website. This order is then sent to a barcode inventory tracking system, such as the BellHawk BITS system where it is converted into an order to ship products to the customer. The ship order is then used to generate a Pick Order listing all the items to be picked for that order.

This Pick Order can then be used to generate a barcoded Picking Sheet on an office printer, as shown below:  


This picking sheet has a pick order barcode (1) and a barcode (2) for each of the items to be picked as well as a suggested location from which to pick this item (3).

The picking sheet will direct the user as to what items to pick but, in order to prevent picking mistakes we must:

  1. Pick the correct items, which requires accurately tracking materials.
  2. Put the items into the correct shipping box or tote for the customer order.

Tracking Materials

In order to ensure picking the correct items, we need to track materials in a number of ways:

  • By putting these materials as "loose" material on a shelf or rack location with a "location" barcode, such as shown at right,  that can be used to uniquely identify the materials on each  shelf.
  • By putting a unique tracking barcode on bins into which the materials are placed. In this case, each bin only holds a single type of item, such as a small, yellow T-shirt or an extra-large blue T-shirt, in a specific style.
  • By putting a unique tracking barcode on each box or other container of materials and then recording where it is put away by scanning the barcode on the container and the location barcode for the shelf or rack where the container is stored. In this case each box or other container only holds a single type of material.
  • By putting a unique tracking barcode on each item with a serial number so this can be scanned to identify the item. The location of the item is recorded by scanning the barcode on the item and the barcode of the location or bin where it is placed.

The tracking barcodes applied to bins, boxes, and individually barcoded items can be printed out on barcode label printers. Alternately, for simplicity, they can be purchased as pre-printed rolls of uniquely numbered "license-plate" tracking barcodes, such as shown at right, which can simply be peeled off and applied to the boxes, bins, or individual items to be tracked.

When bins are set up, the barcode of the bin is scanned together with the location barcode for the shelf on which the bin is placed. In this way the system knows the location of each bin.

When loose materials, such as stack of small yellow T-shirts in a specific style, are entered into inventory then their location is recorded by scanning the barcode on the rack or bin onto/into which they are placed and then the type of items and their quantity is recorded using a mobile device.

When boxes of material or individually serialized items are received then a tracking barcode can be applied to each box and/or serialized item and the data is recorded about the items and the quantity in each box. The location of these materials is then recorded by scanning the tracking barcodes on the boxes or item, along with the bin or location barcodes in which they are placed.

Ensuring Pick Accuracy

When picking items for a specific order, the pick order barcode is scanned from the barcoded picking sheet.  Then, for each item to be picked, the item barcode is scanned from the sheet, typically using a wireless mobile device with an integral barcode scanner. The user will then be directed to the location and/or bin from which to pick the selected material in FIFO order.

The user will then scan the "source" barcode on the shelf, bin, box, or item that uniquely identifies the item being picked and the barcode tracking system will warn the user if they are about to pick the wrong item.

 The next step in making sure that the materials are being placed in the correct shipping container or tote for the customer order. To achieve this, a tracking barcode can be applied to each shipping carton which is designated as being for a specific customer. Alternately we can use totes with permanently attached metal barcodes and designate the totes, temporarily, as being for a specific customer order.

Once the user of the system has scanned the "source" barcode they can then scan the barcode on the "destination" carton or tote and are warned if this container is not designated to receive the order being picked.

In this way we are able to ensure that the correct items are being picked into the correct shipping containers or totes from which they will be subsequently processed.

This does not solve the problem of picking the correct quantity but, for many applications where only one or a small number of each item is being picked, it solves the major problem of accidentally picking a look-alike product or shipping an item to the wrong customer.


There are many variations on this theme, such as allowing for mixed parts on a shelf or in a bin and differentiating between then by scanning the GTIN or UPC barcode on the item. But the same basic principles apply.

Picking using barcoded picking sheets works well when a limited number of large items are being picked. For picking many small parts, the use of a picking sheet can become cumbersome and systems like BellHawk use a paperless picking methodology for this case.

In paperless picking, the user is directed by their mobile device to different zones in a warehouse and are then directed to efficiently pick different items within the zone. For each item all the user has to do is to scan the source and destination barcodes for each item they are directed to pick from and to. This is to enable the system to warn the user if they are picking the wrong item or putting the picked items into the wrong shipping carton or tote.

This zone picking can be extended to allow the directed picking of multiple orders at the same time to multiple cartons or totes on a picking-cart, which can make for more efficient picking. With the use of powered picking carts, weighing scales can also be incorporated under the cartons or totes to do a weight check on the quantity picked.

Barcode inventory tracking systems, such as the BellHawk BITS system, are available for use over the Internet on a subscription basis for a few hundred dollars a month, making the application of these methods cost-effective for all but the smallest E-Commerce retailers.


In order for these methods to work, it is important that the barcode tracking system is able to track materials using "license-plate" container tracking methods. This container tracking of materials is very different from the way most ERP, accounting, or warehouse management systems track inventory, which is to track quantities of material at fixed locations.

Barcode inventory tracking systems, such as BellHawk, which do license-plate container based tracking of inventory, are uniquely suited to inexpensively solving picking accuracy problems.


Dr. Peter Green is the CTO for BellHawk Systems Corporation. He is an expert in using barcode, RFID, and Artificial Intelligence technologies to solve operations tracking and mistake prevention problems for manufacturing, industrial, medical, and other organizations.


Other Barcode news of interest:

3 Essential Asset Tracking Tips for Schools: Automate, Plan and Collaborate with IT
Enterprise Barcode Labeling Software A Key Component for Global Food Supply Chain
2017 Top 5 Trends in Enterprise Labeling
Barcode Labeling Case Study: Manufacturer Achieves Substantial Benefits
Case Study:Winery Chooses New eCommerce Platform And Achieves Great Results
Generation Z: Taking the Food Scene by Storm


Tagged under barcode