What is Replenishment in a Warehouse Management System (WMS)?
- Sep 2, 2022
- 3 min read
Updated: 2 days ago
WMS Back to Basic, Part 10 - Replenishment tasks in a warehouse management system.
Replenishment is the process of moving inventory from non-pickface locations (also known as reserve or bulk storage locations) to pickface locations within a warehouse.
A pickface (sometimes called a forward-picking location) is a location specifically set up for loose picking. Loose picking typically refers to picking quantities less than a full carton, and in many operations, it also includes quantities less than a full pallet. Pickfaces are designed to support fast, high-frequency order fulfillment. (see What is a Pickface for more detail)
Why Replenishment Matters
As picking activities continue, inventory in pickface locations will gradually be depleted. Without timely replenishment, picking operations slow down or stop entirely. Different warehouses adopt different replenishment approaches.
For example:
Some operations prefer to perform replenishment early in the morning to align with manpower planning.
Others trigger replenishment only when needed, based on real-time demand.
To ensure replenishment tasks are executed promptly and picking operations run smoothly, a Warehouse Management System (WMS) is essential. More importantly, the WMS must provide flexibility in replenishment strategies to adapt to different operational requirements.
Common Types of Replenishment
In general, replenishment can be categorized into three main types:
Demand-Based Replenishment
Replenishment tasks are generated based on demand.For example, when active orders require more inventory than what is currently available in the pickface, the WMS automatically creates replenishment tasks to fulfill the shortfall.
Top-Up Replenishment
Top-up replenishment is used to refill pickfaces up to a predefined maximum level, typically during off-peak hours.This approach helps ensure pickfaces are fully stocked ahead of high-volume picking periods.
Ad-Hoc Replenishment
In some situations, warehouse operations may need to create replenishment tasks manually and on demand.Ad-hoc replenishment provides operational flexibility for exceptions, urgent orders, or special handling scenarios.
Pickface Design and Replenishment Triggers
Because loose picking is usually performed manually by a warehouse operator (commonly referred to as a picker), pickfaces are most often located at the ground level of racking systems, where items can be easily reached.
In eCommerce warehouses, pigeonhole locations are commonly used as pickfaces to support high-SKU, small-quantity picking.
As pickers pick inventory from pickfaces, stock levels continue to decrease. When inventory falls below a predefined threshold, the WMS automatically triggers replenishment tasks, directing warehouse personnel to move stock from an appropriate reserve location.
Inventory Rotation and Replenishment Rules
A modern WMS determines the optimal replenishment source location based on configurable rules. These rules ensure proper stock rotation and compliance with operational or regulatory requirements, including:
FIFO (First In, First Out)
LIFO (Last In, First Out)
FEFO (First Expired, First Out)
LEFO (Last Expired, First Out)
By combining intelligent replenishment logic with flexible configuration, a WMS helps warehouses maintain high picking efficiency, reduce stockouts, and ensure accurate inventory rotation.
In addition to the tips outlined in this article, there are many valuable resources available to help you improve your warehouse operations. Two highly recommended reads are Dodge It If You Can and Sh*t Happens in Warehouses and Logistics. These books share real-life incidents and hard-won lessons from industry veterans, offering practical insights into navigating operational challenges, avoiding costly mistakes, and building resilient processes. Whether you’re just starting out or aiming to elevate your warehouse management to the next level, both titles provide valuable perspectives for improving business performance.
Read more on What is a Warehouse Management System:
Contact us for a Demo of Cloud Native Warehouse Management System.