Kitting is when your 3PL turns several products into one sellable unit, such as a gift set, a variety pack, a starter kit or a subscription box. If you only need the definition, the glossary entry has it. The decision that shapes your cost, your inventory and your holiday shipping speed is when each kit gets built: ahead of orders, or as each order comes in.
Pre-build or build to order
Pre-building means the warehouse assembles a batch of finished kits before anyone orders them. Each finished kit gets its own SKU, sits on the shelf ready to go, and ships as fast as a single item. The assembly work is done before any of those kits sell, and the components inside them are no longer available to sell on their own.
Building to order means the components stay loose on the shelf. When an order comes in, the packer picks each item and assembles the kit right then. Nothing is committed until a customer buys, and customers can mix and match. The tradeoff is that every order takes longer to pack than a single item, which matters most during the peak weeks when you want orders out fastest.
Pre-built kits | Built to order | |
|---|---|---|
Best fit | Fixed combinations with predictable demand: a holiday gift set, a starter kit, a subscription run that ships on one date | Mix-and-match bundles, new bundles you're testing, components that also sell on their own |
Inventory | Components are locked into finished kits | Components stay free until an order arrives |
Risk | Components and assembly labor are committed before kits sell; unsold kits stay in stock, get discounted or get taken apart | Kits are assembled only after a customer orders one |
Packing speed | Ships like a single item | Each order takes extra picks and assembly at the packing station |
Changes mid-season | Hard: the built kits are already built | Easy: change the bundle listing and the packing instructions |
If you're not sure demand will hold, there's a middle path: pre-build a conservative batch for the dates you know will be busy and build the rest to order. You can always build more once you've seen a few weeks of sales. Unbuilding kits that didn't sell (de-kitting) is labor too, so it costs money rather than saving it.
How kits show up in Shopify inventory
How you list the kit in your store should match how the warehouse builds it.
For kits built to order, a Shopify bundle does most of the work. Shopify gives the bundle its own SKU but tracks stock through its parts: Shopify's bundle rules say "the product with the lowest inventory level determines how many bundles can be sold." So if you have 400 candles and 120 matching tins, both tracked in Shopify and set to stop selling at zero, the store will only sell 120 candle-and-tin sets. Two other rules matter for planning: bundles can't contain other bundles, and they don't get their own shipping profile, so shipping is calculated from the individual products inside.
For pre-built kits, list the finished kit as its own product with its own SKU and stock count, and treat the warehouse's count of finished kits as the number you can sell. Once components go into a kit, take them out of the stock you sell individually, or your store will show items you no longer have loose.
Whichever way you go, place a test order before launch and check what reaches the warehouse: the bundle as one line, or each component as its own line. The answer tells you whether the packing instructions and stock counts line up.
What to send your 3PL before kitting starts
A 3PL can only build what it can see and count. Before the first kit is built, it needs:
- The components, in bulk, each labeled with a barcode or SKU the warehouse can scan.
- The packaging the kit ships in: the box, any insert or divider, tissue or crinkle paper, stickers or seals, and the cards or flyers that go inside. Don't assume the warehouse stocks presentation materials. ShipBob, for one, states plainly that it doesn't provide zip lock bags, clear plastic or similar materials for kitting.
- A kit spec (sometimes called a bill of materials): every SKU in the kit, how many of each, the order and arrangement they go in, and how the box is closed and labeled. A photo of one finished kit settles most questions faster than a paragraph does.
- The kit's own SKU and barcode, if you're pre-building, so finished kits can be stored and counted separately from their components.
- Quantities and dates: how many kits to build, by when, and whether to hold back loose components for build-to-order sales.
- What to do when something's short or damaged: build fewer kits, substitute an item, or wait for more stock. Sending a few extra of any fragile or printed component gives the warehouse room to replace damaged pieces without stopping the run.
How far ahead to plan a holiday kit
Work backward from the first day you want kits shipping to customers:
- Kit spec and packaging ordered. Custom boxes and printed inserts are made to order and can't be rushed at the warehouse, so order them first.
- Components and packaging arrive at the warehouse. Inbound freight needs a delivery date, not a "sometime that week".
- Receiving. Everything is counted and checked before assembly starts. At Simpl that takes 1 to 3 days after arrival.
- Assembly. Build time depends on how many items go in each kit, how many kits you need and how fiddly the packing is. As one reference point, ShipBob suggests setting up seasonal kitting projects two to three weeks before you need them and allowing one to three business days for pre-kitting.
- Kits on the shelf and live in your store. Only switch the listing on once the warehouse's finished count is in.
A late box order holds up every step after it. If you're building for Black Friday and the holidays, get the spec and the packaging order settled before you think about the build.
How 3PLs charge for kitting
Kitting is hard to price from a rate card, because the work varies so much from one kit to the next. A two-item sample pack and a ten-item gift box with tissue, a card and a ribbon are different jobs. Expect a quote based on your kit, priced per kit or per hour of labor, on top of the regular fulfillment fee for shipping each order. ShipBob, for example, lists pre-kitting as available "at an additional cost" without a published per-unit price.
To compare quotes fairly, ask each 3PL the same questions:
- Is the price per kit, per item placed, or per hour?
- Is building to order priced differently from pre-building?
- Are packaging materials yours to supply, or theirs at a cost?
- What does de-kitting cost if a batch doesn't sell?
- How much notice do they need before a seasonal run, and how fast can they build?
Then do the math on your own numbers: the cost of the build, plus the fulfillment cost per order, plus the cash tied up in pre-built kits you haven't sold yet.
Kitting and assembly at Simpl
Kitting and Assembly is one of our standard services, done in-house at our warehouse in Austin, Texas. We build bundles, gift sets, variety packs, sample packs, promotional kits and subscription boxes from the components you send, either pre-built ahead of time or assembled as orders come in, and then ship each kit like any other order. Gift wrapping and handwritten notes are available when the kit is a gift.
There's no published kitting rate; we quote it per bundle along with your fulfillment quote. Does Simpl do kitting and bundles? covers what we build and how pricing works. If your kit ships on a recurring schedule, subscription box fulfillment covers cycle calendars and inbound timing. For everything else we do day to day, see ecommerce fulfillment.
Send us the list of what goes in each kit and roughly how many you expect to sell, and we'll price the build with your fulfillment quote.