Warehouse picking: improving speed and accuracy with a WMS

Executive summary

• Picking performance depends above all on travel time, stock reliability and the ability to group tasks without creating errors.
• The most effective method varies with order profile: single-order, batch, wave, zone and goods-to-person flows each answer a different operational need.
• A WMS creates value when it prioritizes missions in real time, secures scans, synchronizes replenishment and gives supervisors clear visibility.
• Lasting gains come from combining software, slotting discipline, ergonomics, traceability and regular review of storage rules.

Definition of picking in a "manual", semi-automated and 100% automated warehouse

Picking is the action of the "picker" who fetches ordered items, and assembles them for packing and dispatch. In a manual warehouse, these trips can add up to several kilometers a day... Picking is governed by two main principles: the "man-to-item" process, in which the order picker travels to fetch the products; and the "item-to-man" process, in which the item comes to the operator, thus limiting his travels, which can only take place in automated or semi-automated warehouses. This is a dynamic picking configuration, which changes according to logistical challenges, such as product seasonality, or the volume of items to be picked.

In the "man-to-item" process, several methods can be applied: the Pick and Pack method, which requires the picker following a printed list to pick items for one or more orders, and bring them to the packing area. The Put to Light method involves equipping operators with a display caddy, which indicates the location of the items, and where they are to be deposited. Finally, the Pick by Light method also uses lights and messages, which are displayed at the storage location where the items to be picked are located. This makes it easy to see where each item is to be picked. Each of these methods obviously requires a different type of equipment, with varying degrees of cost.

In semi-automated warehouses, for the "item-to-man" process, new technologies are continuously improving the operation of logistics warehouses. Picking can be carried out in two different ways: either robots bring the items to the packing area, or a central conveyor brings them there, as in industrial chains. Computerized processes, such as voice-activated order-picking systems, guide operators, and automated mechanisms help pack orders. However, this requires a number of parameters to be taken into account: starting with shelving, dynamic racks and shelving units, which need to be adapted to the chosen picking method; a precise labeling system to assist the operator with optimal product traceability; electronic terminals to locate the picking location and the place where orders can be deposited for packing; and finally, handling aid equipment, such as connected trucks, forklifts or pallet trucks.
Other large warehouses are 100% automated and computerized. In these cases, data alone determines the operators' picking path.

Beyond the choice between "man-to-item" and "item-to-man", picking strategy is now closely linked to omnichannel retail. The same warehouse may have to prepare store replenishment, e-commerce parcels and urgent B2B orders in parallel. This makes stock accuracy, location data quality and task prioritization even more critical, because the picking method must adapt to different order sizes, cut-off times and service levels without slowing the overall flow.

Another point often underestimated is ergonomics. Good picking performance is not based only on software or automation: clear signage, accessible fast-moving items, suitable container sizes and fewer unnecessary touches all help limit errors and fatigue. In practice, a well-designed workstation and consistent location labeling improve both productivity and operator comfort, especially during peak periods.

Different picking methods

Warehouse picking management is based on the supply chain, i.e. on the location of items and their purchase recurrence. A basic adaptation of the ABC storage method is very common, except for perishable products where the FIFO method (first in first out) must be applied, whatever the volume of shipment.
Finally, the weight of products must also be taken into account, with the heaviest items being picked first and placed at the bottom of the shelves, while the lightest are stored high up. In reality, there are as many picking methods as there are warehouse management options: from single-order picking (a single item picked and processed), to multi-order picking, in batches or waves, which enables several orders to be prepared within a given timeframe, for a given carrier or specific customers.

To this classic segmentation, many warehouses add zone picking, cluster picking and hybrid flows. Zone picking assigns each operator to a defined area, which shortens travel time in large sites. Cluster picking lets one route serve several orders at once, which is useful when many orders share the same references. Hybrid models are increasingly common because they reserve the most efficient method for fast movers, bulky goods or urgent lines.

For products with expiry constraints, FEFO logic can also complement or replace simple FIFO, since the nearest expiry date-not only the arrival date-determines the best picking sequence. This is particularly relevant wherever traceability and shelf-life control are part of service quality.

The choice of method should also be reviewed regularly through slotting analysis. If the most frequently picked SKUs are not stored in the most accessible locations, even a disciplined team loses time. Reassigning locations according to seasonality, promotions, returns and new product launches is one of the simplest ways to improve pick rates without heavy investment.

The advantages of a WMS in optimizing picking

In view of all the above parameters, it's clear that a WMS is an essential ally in the management of your warehouse. It enables you to calculate optimized picking times for your operators, which translates into immediate productivity gains. It also guarantees reliable order picking.

Concretely, a WMS improves picking by assigning tasks according to priority, operator profile and zone availability. It can sequence missions, consolidate compatible orders, guide scans, manage exceptions and launch replenishment before a shortage blocks preparation. This coordination role is particularly valuable when several technologies coexist in the same warehouse: RF terminals, voice picking, pick-to-light, conveyors or robotic stations.

It also provides a factual basis for continuous improvement. Supervisors can compare preparation times, analyze recurring errors, identify congested aisles and monitor the impact of slotting or staffing decisions. Used well, these indicators help balance service level, labor productivity and storage density, instead of managing the warehouse by intuition alone.

That said, a WMS delivers its full value only if master data, location mapping and operating rules are kept up to date. Poorly maintained item dimensions, inconsistent labels or delayed stock adjustments can reduce the benefits of even the best software. In other words, digital orchestration is most effective when paired with disciplined warehouse processes.

In conclusion, the WMS is a must for increasing the speed and reliability of order picking in the warehouse. Order-picking times will be reduced, inventory management optimized, and handling facilitated.

FAQ

• What is the difference between pick and pack and batch picking? Pick and pack generally means picking items and sending them directly to packing for one order or a limited set of orders, whereas batch picking groups several orders in one route and sorts them afterwards.
• Do you need automation to improve picking? No. Many warehouses first gain productivity through better slotting, scan discipline, replenishment management and WMS task orchestration.
• Which KPIs are the most useful for monitoring picking? Travel time, lines picked per hour, pick accuracy, replenishment delays and order completion rate are among the most practical indicators.
• How does a WMS reduce picking errors? It validates locations and barcodes, guides operators step by step, prioritizes tasks and keeps stock data synchronized with the physical flow.