Amazon FBA has changed the economics of running an online retail business. The ability to send stock to Amazon's warehouse and let Amazon handle fulfilment, customer service, and returns has removed one of the biggest barriers to scaling: the operational complexity of picking, packing, and shipping hundreds of individual orders. For sellers sourcing wholesale FMCG products, FBA has opened up a genuinely compelling route to market, and the UK wholesale supply chain is well placed to serve it.

This guide is specifically for sellers who are either starting out with Amazon FBA or who are looking to sharpen how they approach it. It covers the mechanics of how FBA works, how to choose the right products, how to source them through a reliable UK wholesale supplier, how to prep and label stock correctly, and what to watch out for as your FBA operation grows.

If you are already selling on Amazon through merchant-fulfilled listings and are considering the switch to FBA, this guide will help you understand what is involved. If you are starting from scratch and want to build an FBA business on a solid foundation, the same applies.

How Amazon FBA Works

FBA stands for Fulfilment by Amazon. The model is straightforward in concept. You source products, prepare them according to Amazon's requirements, and send them to one of Amazon's fulfilment centres. When a customer on Amazon.co.uk buys one of your products, Amazon picks it, packs it, and ships it. If the customer wants a return or has a service query, Amazon handles that too.

In exchange for this service, Amazon charges fees. There are two main types: referral fees and FBA fees. The referral fee is a percentage of the sale price, typically between 8% and 15% depending on the product category. The FBA fee is charged per unit and covers the cost of picking, packing, and shipping, calculated based on the size and weight of the product. There are also storage fees, charged per cubic foot of space your stock occupies in Amazon's warehouse, which increase significantly for stock that has been in the warehouse for more than a year.

The primary commercial advantage of FBA is the Prime badge. Products fulfilled by Amazon qualify for Prime delivery, which means next-day or two-day delivery for Prime members. Prime membership in the UK is substantial, and Prime members convert at significantly higher rates than non-Prime buyers. For most product categories, being in FBA rather than merchant-fulfilled results in meaningfully higher sales volume, all else being equal.

FBA also helps with the Buy Box. Amazon's Buy Box is the default purchase button on a product listing, and the algorithm that determines who wins it favours FBA sellers, particularly on competitive listings with multiple sellers. Winning the Buy Box consistently is essential for volume in most categories.

The trade-off relative to merchant fulfilment is cost and complexity. FBA fees add up, and for lower-value or heavier products they can significantly compress margins. Managing FBA also requires attention to inventory levels, inbound shipment preparation, and compliance with Amazon's labelling and packaging requirements. None of this is technically difficult, but it does require discipline and consistency.

Why FMCG Products Work Well for FBA

Not all product categories suit FBA equally. The economics work best for products that are light and compact relative to their sale price, that are purchased with consistent frequency rather than once in a lifetime, and that buyers are comfortable purchasing without handling the product first. FMCG goods, particularly toiletries, personal care products, household goods, and home fragrance, tick most of these boxes.

Weight and size matter because they drive FBA fees. A shampoo bottle that weighs 250g and fits in a small parcel incurs considerably lower FBA fees than a set of kitchen knives that requires a large, heavy box. For most FMCG products in the personal care and household categories, the size and weight profile means FBA fees are manageable relative to a reasonable sale price.

Repeat purchase frequency matters because it creates stable, predictable demand. Customers who buy toiletries and household essentials online tend to reorder from the same seller if they had a good experience, which means a well-run FBA listing in a consumable category builds a recurring revenue base over time rather than relying entirely on new customer acquisition for every sale.

Brand recognition matters on Amazon because buyers search by product name or brand rather than browsing in the way they might in a physical shop. A product from a recognised brand such as Febreze, Colgate, or Yankee Candle already has search demand attached to it. Buyers are looking for that product specifically, and a well-priced listing from an FBA seller can capture that demand without requiring the seller to build brand awareness from scratch.

Own-label and exclusive products offer a different kind of advantage. On a branded listing shared with multiple sellers, the Buy Box is contested on price, which compresses margins over time. On a product that is exclusive to a particular supplier or a supplier's own brand, there is no shared listing to compete on, which means your pricing power is significantly stronger. For FBA sellers looking to build sustainable margins, finding products that are not widely distributed is one of the most valuable things you can do.

Choosing the Right Products for FBA

Product selection is where FBA businesses are built or broken. A well-chosen product line can generate consistent, growing income. A poorly chosen one ties up capital, incurs storage fees, and eventually has to be cleared at a loss. The discipline of choosing carefully matters more than almost anything else in the early stages.

Price Points That Work With FBA Fees

As a working rule, products selling below £5 on Amazon are very difficult to make profitable through FBA. The referral fee and FBA fee combined will typically consume more than half the sale price, leaving insufficient room for the trade cost and a reasonable margin. Products in the £6 to £15 range are the most common sweet spot for FMCG FBA sellers, where fees are manageable and the margin structure is workable. Higher-value products, such as premium gift sets or large-format personal care items, can support FBA economics more comfortably still, though they often carry higher trade costs that need to be factored in.

Categories That Perform

In the context of FMCG wholesale sourced through a UK distributor, the categories that tend to perform well for FBA sellers are personal care and toiletries, home fragrance including air fresheners, candles, and wax melts, haircare, household cleaning products, and health and beauty. Gift sets perform well in the run-up to key gifting occasions and can deliver strong margins if bought well and timed correctly.

Consumables generally outperform durables for FBA because of repeat purchase behaviour. A customer who orders shower gel and has a good experience will reorder when they run out. A customer who orders a single-purchase item does not. Building your range around consumables creates a more predictable revenue base.

Restricted Categories and Ungating

Some categories on Amazon require approval before you can list products in them. Health and beauty is one of the most common categories where ungating is required, particularly for branded products. The process for getting approved typically requires you to provide a recent invoice from an approved wholesale supplier, showing that you have purchased genuine product in commercially reasonable quantities. This is not an onerous requirement if you are buying through a legitimate UK wholesale distributor, but it does mean you need proper documentation from your supplier. Informal purchasing from market traders, car boot sales, or unofficial channels will not provide what Amazon requires.

Before sourcing a product line, check whether the specific brand or category requires approval on Amazon. Some brands actively enforce authorisation, meaning that even with a legitimate invoice you may not be approved to sell their products. It is better to discover this before you have placed a wholesale order than after.

Products to Approach With Caution

Certain product types create disproportionate risk for FBA sellers. Liquids and gels require specific packaging to pass Amazon's drop test, and products that fail on arrival at the fulfilment centre will be returned to you at your cost. Pressurised aerosols have specific labelling and storage requirements in Amazon's fulfilment centres. Products with short shelf lives, typically anything with a best-before date less than 90 days away at the time of check-in, are liable to be refused. Understanding the requirements for your specific product types before you source is important, because non-compliance results in returned or disposed stock and associated costs.

Finding a Wholesale Supplier for FBA

The requirements that matter most when choosing a wholesale supplier for FBA are somewhat different from what matters most for a traditional retailer. FBA has specific practical needs that not all wholesale distributors are well placed to serve.

Proper VAT Invoicing

This is the single most important practical requirement. Amazon may ask you at any point to verify the provenance of products you are selling, particularly for brand-gated categories or in response to a complaint. The documentation they require is a recent invoice from an authorised wholesale distributor, showing the product, quantity, price paid, and your business details. A legitimate UK wholesale supplier will provide this as a matter of course. Make sure you retain all invoices from your supplier and that they show sufficient detail.

Stock Consistency

Running out of stock on an FBA listing has a direct cost beyond the immediate lost sales. Amazon's algorithm takes inventory levels into account when determining ranking and Buy Box eligibility. A listing that goes out of stock and then comes back in takes time to recover its position, during which you are losing sales to competitors. Sourcing from a supplier with reliable availability on your key lines, and building your reordering schedule to maintain healthy stock levels in Amazon's warehouse, is significantly more important for FBA than for a bricks-and-mortar shop where a temporary gap can be managed without algorithmic consequences.

Case Quantities and Pallet Orders

FBA economics generally favour sending stock in larger quantities less frequently rather than small quantities constantly. Each inbound shipment to Amazon carries a cost, including your time, any prep work, and Amazon's own inbound placement fees. Ordering in full case quantities, and consolidating multiple product lines into a single pallet delivery where possible, reduces the per-unit cost of getting stock into Amazon's warehouse.

A wholesale supplier who can accommodate pallet-quantity orders and who operates their own delivery fleet is particularly well suited to FBA sellers. Northern Marketing operates a 40,000 square foot warehouse in Nelson, Lancashire, with its own UK delivery fleet, which means FBA sellers can order in quantities that make sense for their FBA workflow without relying on third-party couriers or dealing with multiple part-pallet deliveries from different suppliers.

Repackaging and Custom Labelling

Some wholesale products need to be repackaged or relabelled before they are FBA-ready. This might be because the original packaging is not suitable for individual sale, because the product needs to be bundled with another item to create a new ASIN, or because the seller wants to list the product under their own brand rather than the manufacturer's. Northern Marketing offers in-house repackaging and custom labelling services, which means FBA sellers who need to modify how products are presented before sending to Amazon can have this handled at the source rather than managing it themselves or through a separate prep centre. For sellers building a private label or own-brand FBA operation, this capability is a genuine operational advantage.

Prep and Labelling: Getting Your Stock FBA-Ready

Amazon has detailed and specific requirements for how products must be prepared and labelled before they are sent to a fulfilment centre. Compliance with these requirements is not optional. Stock that arrives at a fulfilment centre in a non-compliant state will be returned, relabelled at your expense, or in some cases disposed of. Understanding the requirements for your specific product types before you send your first shipment saves you significant time and money.

FNSKU Labels

Every product sent to Amazon FBA must have an FNSKU label applied. FNSKU stands for Fulfilment Network Stock Keeping Unit, and it is the barcode Amazon uses to identify your specific inventory as distinct from another seller's inventory of the same product. You generate FNSKU labels through Seller Central and apply them to each unit, either over the manufacturer's barcode or in addition to it depending on Amazon's requirements for that product type.

For most FMCG products, applying FNSKU labels manually to each unit is the most common approach for smaller operations. As volume grows, some sellers use a prep centre to handle labelling, or, where the facility exists, arrange for their wholesale supplier to apply labels before dispatch. If this is a service you would find useful, it is worth discussing with your supplier at the outset rather than assuming it is available.

Poly-Bagging and Packaging Requirements

Certain product types must be poly-bagged before they can be sent to FBA. Products that have loose parts, products that could leak, products with multiple components, and products that Amazon considers fragile may all require specific packaging. Amazon publishes detailed prep guidance for each product type in Seller Central, and it is worth consulting this before your first shipment rather than discovering non-compliance at the fulfilment centre.

Liquids and gels are a common category for FMCG sellers and carry specific requirements. They must be sealed in leak-proof packaging with a sufficiency test that allows the product to survive a drop from a height. If your wholesale product comes in packaging that does not meet this requirement, you will need to overpack it before it is FBA-eligible. This adds a prep step that affects your economics and should be factored into your margin calculation.

Bundling

Creating bundled ASINs, listings that combine two or more products sold together as a single unit, is a legitimate and often effective FBA strategy. Bundles can improve margin by increasing the average sale price without proportionately increasing FBA fees, and they reduce the number of competing sellers on your listing because bundles cannot be shared in the same way as single-item listings. A bundle of three shower gel variants, for example, creates a new listing that other sellers cannot simply jump onto.

Creating a bundle requires some prep work: the bundled units need to be packaged together and labelled with a new FNSKU for the bundle ASIN. If your wholesale supplier offers custom packaging or multipacking services, this can be handled efficiently at source. Otherwise, it is a task that falls to you or a prep centre.

Carton and Pallet Labelling for Inbound Shipments

When you create an inbound shipment in Seller Central, Amazon generates carton labels that must be applied to every box in the shipment. For pallet shipments, there are additional pallet labels. These labels allow Amazon to process your inbound stock quickly and accurately. Applying the wrong label to the wrong box, or sending cartons without labels, results in delays, additional fees, and in some cases the shipment being rejected at the fulfilment centre.

Building a standard operating procedure for your inbound shipment process, even at an early stage, reduces errors and makes it easier to delegate or scale later. Document the steps involved, the label placement requirements for your specific product types, and the carton content record that must accompany each shipment. It is unglamorous but genuinely important.

Managing Your FBA Inventory

Once your stock is in Amazon's fulfilment centres, inventory management becomes the ongoing operational discipline that has the most direct impact on your profitability. FBA sellers who manage their inventory well maintain strong IPI scores, avoid long-term storage fees, and keep their listings live without running out of stock. Those who do not tend to face a combination of excess stock charges, lost ranking from stockouts, and stranded inventory that ties up capital without generating sales.

How Much Stock to Send In

The right quantity to send to Amazon at any one time is a function of your rate of sale and your supplier's lead time. If a product sells 20 units per week and your supplier needs five days notice plus your prep and shipping time adds another three days, you need enough stock in Amazon's warehouse to cover approximately two weeks of sales as a minimum, plus a buffer. Sending in significantly more than this ties up capital in Amazon's warehouse and incurs storage fees on excess units.

In practice, most FBA sellers aim to maintain between four and eight weeks of stock in the fulfilment centre for their active lines. Enough to avoid stockouts without incurring unnecessary storage costs. As your rate of sale data accumulates over several months, calibrating this becomes easier.

Stranded Inventory

Stranded inventory is stock in Amazon's fulfilment centre that is not associated with an active listing, usually because a listing was closed, suspended, or requires attention. Stranded stock still incurs storage fees but generates no sales, so resolving it promptly is important. Amazon sends notifications about stranded inventory, but checking the Inventory Health report in Seller Central regularly is good practice regardless.

Long-Term Storage Fees

Amazon charges significantly higher storage fees for units that have been in a fulfilment centre for more than 365 days. For FMCG products, which should be turning over relatively quickly, long-term storage fees should not be a regular problem. However, if you order too heavily ahead of a seasonal peak that does not materialise, or if a product line slows significantly, units can accumulate towards the long-term threshold without you noticing. Review your aged inventory report monthly and take action on slow-moving stock before it reaches the threshold, either by adjusting the price to accelerate sell-through or by arranging a removal order.

Inbound Placement Fees

Amazon has introduced inbound placement fees for most sellers, which are charged when Amazon distributes your inventory across multiple fulfilment centres rather than accepting it all at a single location. The fee varies by product size and weight, and there is an option to pay a higher per-unit fee in exchange for sending your entire shipment to a single location of your choosing. For FBA sellers sourcing through a UK wholesale supplier, understanding how inbound placement fees interact with your overall cost structure is increasingly important and should be factored into your margin calculations.

Calculating Your True FBA Margins

A complete margin calculation for an FBA product needs to account for every cost between the wholesale trade price and the net amount Amazon pays out. Sellers who skip this step or approximate it tend to discover the problem in their monthly payout rather than in advance, which is the wrong place to find out.

The components of an FBA margin calculation are: the wholesale trade price per unit, the Amazon referral fee (a percentage of the sale price), the FBA fee per unit (referral and size-tier dependent), inbound shipping cost per unit (the cost of getting stock to Amazon's warehouse divided across the number of units in the shipment), prep and labelling cost per unit if applicable, and any storage fees on a monthly basis divided by your average units sold.

Here is a worked example. A personal care product sells on Amazon at £8.99. The Amazon referral fee for health and beauty is 8%, which is approximately 72 pence. The FBA fee for a small standard product at this weight is approximately £2.80. Inbound shipping from a UK wholesale supplier to Amazon's fulfilment centre runs to roughly 30 to 50 pence per unit when sent in pallet quantities. Labelling takes approximately 10 pence per unit in materials and time. Monthly storage fees, averaged over the year, add perhaps five to ten pence per unit. The total cost of selling is therefore approximately £4.00 to £4.20 per unit before accounting for the trade price.

If the product is available at a trade price of £2.80, the net margin is approximately £2.00 per unit, or about 22% of the sale price. If the trade price is £3.50, the margin drops to approximately £1.30, or around 14%. Whether either of these is acceptable depends on your volume and the time investment required, but the calculation is explicit rather than approximate.

Running this calculation before you source is not optional. Running it again after three months of actual sales, using real costs from your account rather than estimates, is equally important, because the assumptions you make upfront are rarely perfectly accurate.

Common Mistakes FBA Sellers Make With Wholesale Sourcing

• Sourcing without checking Amazon's category restrictions first.
  • Discovering that you cannot list a product after you have already ordered 200 units from your wholesale supplier is an avoidable problem. Check the specific brand and category requirements in Seller Central before placing any wholesale order. Some brands actively restrict third-party sellers; others require straightforward ungating that your supplier invoice can support.

• Choosing a supplier who cannot provide adequate documentation.
  • Amazon's brand registry and ungating processes require invoices that show your business name, the product description, the quantity purchased, and the supplier's details clearly. An informal receipt or a generic delivery note will not meet this standard. Source from a registered UK wholesale supplier who issues proper VAT invoices as a matter of course.

• Underestimating prep complexity.
  • Products that seem straightforward sometimes require more prep than expected, whether because of poly-bagging requirements, labelling complications, or packaging that does not meet Amazon's standards. Factor prep time and cost into your margin calculation from the start, not as an afterthought when your first shipment takes twice as long to prepare as you expected.

• Sending in too much stock on unproven lines.
  • The temptation to send in large quantities of a new product to reduce per-unit inbound costs is understandable, but the risk is significant if the product does not sell at the volume you anticipated. Excess stock in Amazon's warehouse incurs storage fees and creates pressure to discount in order to clear it. Test at modest quantities, establish a rate of sale, and then scale your inbound quantities accordingly.

• Ignoring seasonal storage fee increases.
  • Amazon charges higher storage fees during the peak period from October to December. If you are building up stock ahead of Christmas and some of it does not sell through, the storage costs in that period are significantly higher than the rest of the year. Plan your seasonal buying carefully, using previous sell-through data where available, and do not overbuy.

• Competing on branded listings without a price advantage.
  • On a listing shared with multiple FBA sellers, the Buy Box is typically won on the lowest price among eligible sellers. If your trade price does not give you enough room to be competitive on price while still hitting your target margin, you will lose the Buy Box without necessarily losing money on individual sales, but you will see lower volumes than the economics require to make the business worthwhile. Either find products where your pricing is competitive or focus on own-label lines where the listing is not shared.

Building a Sustainable FBA Business With the Right Wholesale Partner

The FBA sellers who build durable businesses over several years share a few common characteristics. They are disciplined about product selection, running the numbers properly before every sourcing decision. They manage their inventory actively rather than reactively. They treat their supplier relationships as a commercial asset, engaging regularly and communicating clearly. And they are patient about scaling, building volume on proven lines rather than constantly chasing new products in the hope that something performs.

The wholesale supplier you choose is central to all of this. A supplier with consistent stock availability means you can maintain the inventory levels your FBA listings need. A supplier with proper invoicing means you can pass any Amazon documentation check. A supplier with genuine depth in FMCG categories means you can build a coherent range without stitching together orders from five different distributors. And a supplier who offers services like repackaging and custom labelling means your operational complexity stays manageable even as your product range grows.

For FBA sellers focused on FMCG categories, Northern Marketing is worth a serious look. Based in Nelson, Lancashire, we supply online sellers, independent retailers, convenience stores, and exporters across the UK from a 40,000 square foot warehouse, with over 500 SKUs in household goods, toiletries, personal care, home fragrance, and health and beauty.

Our product range includes major brands including Febreze, Air Wick, Fairy, Lenor, Colgate, Yankee Candle, and Garnier, alongside our own exclusive brands including Perfect Scents for home fragrance, ET8 for haircare, and Lumist for personal care. For FBA sellers, the own-brand lines are particularly interesting: because they are exclusive to Northern Marketing's distribution, you will not find them on shared Amazon listings being competed down to a margin that makes the effort pointless.

We offer in-house repackaging and custom labelling, which means FBA sellers who need products modified or relabelled before shipping to Amazon can arrange this at source rather than adding a separate prep step. We provide proper VAT invoicing on every order. Our minimum order value is £250 plus VAT, which makes it practical to test new product lines at modest quantities before committing to larger FBA inbound shipments.

Open a free trade account with Northern Marketing today.

Final Thoughts

Amazon FBA is one of the most accessible and scalable routes to building an online retail business in the UK, and FMCG wholesale products are among the best-suited categories for the model. The combination of consistent consumer demand, manageable size and weight profiles, and a well-developed UK wholesale supply chain creates a genuine opportunity for sellers who approach it with the right discipline.

The mechanics of FBA, the prep requirements, the margin calculations, the inventory management, are all learnable. The part that is harder to shortcut is the sourcing decision: choosing the right products at the right price from a supplier you can rely on. That decision shapes everything else in the business. Take it seriously, do the analysis before you commit capital, and build a supplier relationship that supports your FBA operation properly rather than simply providing a delivery address for stock.

The sellers who succeed with FBA over the long term are almost always the ones who got the sourcing right from the start.