Selling products individually is fairly simple from an inventory standpoint. You sell one item, and inventory for that SKU goes down by one. Things get more complicated when those same products are also sold in bundles, multipacks, gift sets, or kits.
A customer may see one product on the storefront, but behind the scenes that item can depend on several different SKUs being available at the same time. Those components may also be sold individually or included in other kits, which means every sale can affect the availability of several products at once. That is why kitting is more than a merchandising strategy. It is an inventory workflow.
For eCommerce businesses, the goal is to keep the relationship between the sellable kit and its underlying components accurate, so availability stays reliable whether those components are sold individually, inside one kit, or across several different products.
What Is Kitting in eCommerce?
Kitting in eCommerce is the process of grouping multiple products or quantities together and selling them as one item. A kit can be as simple as a three-pack of the same candle or as complex as a gift set made up of several different products.
Imagine you sell a Coffee Lover Gift Set with one bag of coffee, one mug, and two biscotti packs. The customer buys one gift set, but the fulfillment team still needs all four underlying components to complete the order. If the mug sells out, the entire kit becomes unavailable even if the coffee and biscotti are still in stock.
The same challenge appears when those components are sold separately. If someone buys the mug on its own, that sale also affects how many gift sets you can still fulfill. This is where kitting becomes closely tied to eCommerce inventory management. The kit SKU cannot be managed in isolation because its availability depends on the products inside it.
You may also hear this relationship described as a bill of materials, or BOM. In simple terms, the BOM defines what goes into the kit and how much of each component is required. Once that relationship is established, the inventory system can use component quantities to determine how many complete kits are available to sell.
How Kit Inventory Is Calculated
Kit availability depends on the components needed to build the kit.
Suppose your gift set requires:
1 coffee bag + 1 mug + 2 biscotti packs
You currently have:
- 20 bags of coffee
- 12 mugs
- 30 biscotti packs
That means:
- Coffee supports 20 kits
- Mugs support 12 kits
- Biscotti supports 15 kits because each kit requires two
So your actual kit availability is:
12 complete gift sets
The mug is the limiting component because it is the first required item you would run out of.
This becomes especially important when those components are also sold individually or used in other kits. If someone buys a mug on its own, the number of gift sets you can still sell drops too. The kit quantity should reflect that change automatically rather than continuing to show 12 available.
That same logic applies when one component is shared across several bundles. One candle might be sold individually, in a two-pack, inside a holiday gift box, and as part of a subscription set. Those may look like different products on the storefront, but they are all drawing from the same underlying inventory.
Selling Components Individually and Inside Kits
This is one of the biggest reasons eCommerce businesses need a clear kitting workflow.
A component does not stop being inventory just because it is included in a bundle. If it can also be purchased individually, every sale has to be reflected everywhere that component is used.
Suppose you have 50 bottles of hot sauce. You sell the bottle on its own, in a three-pack, and as part of a gift set with two other products. A customer who buys one bottle individually has reduced the inventory available for both the three-pack and the gift set.
If each product is managed as an independent inventory number, those relationships can quickly fall out of sync. The store may continue selling kits based on quantities that no longer exist, increasing the risk of overselling and creating a fulfillment problem after the order has already been placed.
This is why kits and bundles benefit from the same connected inventory approach we discussed in our guide to preventing eCommerce stockouts. Knowing how much inventory you have is useful, but you also need to understand how that inventory is being consumed across the catalog.
Virtual Kits vs. Pre-Assembled Kits
Not every kit has to be physically assembled before it is sold.
Some businesses pre-build kits and store them as finished products. Others keep the components separate on the shelf and assemble the kit only when an order comes in. Both approaches can work, but they create different inventory needs.
A pre-assembled kit may need its own physical stock count because the components have already been removed from individual inventory and turned into a finished product. If the kit is later taken apart, those components may need to be returned to their original inventory quantities.
A virtual kit works differently. The individual components remain available as their own products until the kit is sold. The system uses the BOM relationship to calculate how many kits could be fulfilled based on the available components.
Virtual kits can give businesses more flexibility because the same inventory can support several different sellable products without requiring everything to be assembled ahead of time. That can be especially useful for gift sets, multipacks, promotional bundles, or products that change seasonally.
The right setup depends on how the warehouse operates, how often kits are sold, and whether assembly happens before or after the customer places the order.
How Kitting Affects Replenishment
Kitting also changes the way a business thinks about purchasing and replenishment.
You may not sell a component very often on its own, but it could still move quickly because it appears inside several popular kits. Looking only at standalone sales could make that SKU seem slower than it really is.
That is where inventory forecasting becomes more important. Demand for a component includes all of the ways that item is being consumed, not just the orders where customers purchase it individually.
The same principle applies to reorder points. If a component is essential to several high-volume kits, waiting until its standalone inventory looks low may be too late. Running out of one small component can suddenly make several profitable products unavailable at once.
Purchase orders can help connect that replenishment back to suppliers. When components reach the point where more inventory is needed, a clear purchase order workflow makes it easier to track what has been ordered, what is still on the way, and when those kits may have more inventory available again.
For businesses with seasonal kits or predictable bundle demand, safety stock can also provide a cushion for components that would otherwise become a bottleneck.
Kitting Across Warehouses and Fulfillment Workflows
Kitting gets another layer of complexity when inventory is spread across multiple locations.
A kit might technically have enough component inventory across the entire business, but that does not always mean one location can fulfill it. If the coffee is in one warehouse and the mug is in another, the overall inventory totals may look healthy while the actual order still cannot be packed in one place.
That is why kit inventory needs to be considered alongside warehouse management and the broader eCommerce order fulfillment process.
The same idea applies to virtual warehouses. A business may separate inventory by physical location, supplier, sales channel, subscription program, or another fulfillment workflow. Kit availability may need to reflect which components are available within the inventory pool responsible for fulfilling that particular order.
As the catalog grows, these relationships become harder to manage manually. A spreadsheet may tell you how many units of each component exist, but calculating the number of available kits across several products and locations can quickly turn into a lot of formulas and constant updates.
How Ordoro Handles Kitting
Ordoro connects kit inventory to the components that make up the finished product.
Businesses can define kits using BOM relationships so inventory availability is based on the underlying components instead of treating the kit as an unrelated SKU. When those components are sold individually or used in other kits, the relationship helps keep the available quantities connected.
Ordoro also supports more complex kit structures, including quantities greater than one and fractional component quantities. That can be useful for businesses where one sellable product consumes part of a larger inventory unit rather than one whole component at a time.
Because kitting lives alongside inventory, warehouse, order, and fulfillment workflows, businesses can manage the relationships behind the product without separating kit availability from the rest of their operations.
You can learn more about Ordoro’s inventory management tools and how inventory connects with purchasing, fulfillment, and shipping across the platform.
Common Kitting Problems to Watch For
Kits can simplify the buying experience for customers while creating more relationships to manage behind the scenes. A few common problems tend to appear as the number of kits grows:
- Treating kit inventory as a separate number that does not change when components sell
- Forgetting that one component may be used in several different kits
- Overselling a kit because one required component has already run out
- Reordering components based only on standalone sales instead of total usage
- Assuming company-wide inventory means a kit can be fulfilled from a specific warehouse
- Pre-assembling too much inventory into kits that may later need to be sold individually
- Managing kit relationships manually across spreadsheets and sales channels
The goal is not to make every bundle complicated. It is to make sure the inventory behind the bundle behaves the way the customer expects the product to behave.
If the storefront says the kit is available, the fulfillment team should have the components needed to ship it.
Frequently Asked Questions About eCommerce Kitting
What is kitting in eCommerce?
Kitting is the process of combining multiple products or quantities into one sellable item. The kit may contain several different SKUs, multiple quantities of one SKU, or a combination of both.
What is the difference between a kit and a bundle?
The terms are often used interchangeably in eCommerce. Both generally refer to multiple products being sold together as one offer. From an inventory perspective, the important part is the relationship between the sellable product and the individual components required to fulfill it.
What is a BOM in eCommerce?
A bill of materials, or BOM, defines the components and quantities needed to make a kit or finished product. The BOM allows an inventory system to understand what inventory is consumed when the kit is sold.
How is kit inventory calculated?
Kit availability is generally based on the component that can support the fewest complete kits. If a kit requires two units of a component and 10 are available, that component can support five kits.
Can kit components also be sold separately?
Yes. This is common in eCommerce. When components are sold both individually and inside kits, inventory needs to stay connected so a standalone sale also updates the number of kits still available.
What happens if one kit component runs out?
If a required component reaches zero, the business can no longer fulfill complete kits that depend on that component, even if every other component remains in stock.
What is a virtual kit?
A virtual kit is a kit whose components remain separate in inventory until an order is placed. The system calculates kit availability from the underlying components rather than relying on a separate stock of pre-assembled kits.
How does kitting affect inventory forecasting?
Demand for kit components includes both standalone sales and the quantities consumed through kits. Businesses need to account for both when forecasting demand and planning replenishment.
Keep the Kit and Its Components Connected
Bundles and kits can give customers more ways to buy products they already want. Behind the scenes, though, every kit creates inventory relationships that need to stay accurate.
A single component may support several products. One standalone sale can reduce the availability of multiple kits. A component stockout can take several products offline at once, and inventory spread across locations can make the picture even more complicated.
The solution is not to stop offering kits. It is to make sure the system understands what each kit is made of and how those components move.
When kit relationships are connected to inventory, purchasing, warehouses, and fulfillment, businesses get a much clearer picture of what they can sell and what they can actually ship.
Ready to manage kits and component inventory without keeping the relationships straight by hand? Start a free trial of Ordoro and see how connected inventory and fulfillment workflows can help.
