FBA means Amazon stores, packs and ships your orders; FBM means you, or a 3PL working for you, do it instead. FBA gives you the Prime badge and hands off customer service and returns, but adds Amazon fulfilment and storage fees and, since July 2026, full responsibility for prepping your stock. FBM gives you more control and avoids Amazon storage fees, but you must meet Amazon’s delivery standards yourself. Many UK sellers use both.
There is no single right answer. The best choice depends on what you sell, how fast it sells and how much control you want over your stock. This guide compares the two side by side and shows when each one makes sense for UK sellers.
FBA vs FBM at a glance
| FBA (Fulfilled by Amazon) | FBM (Fulfilled by Merchant) | |
|---|---|---|
| Who stores the stock | Amazon fulfilment centres | You or your 3PL |
| Who picks, packs and ships | Amazon | You or your 3PL |
| Prime badge | Yes, automatically | Only through Seller Fulfilled Prime |
| Customer service and returns | Handled by Amazon | Handled by you or your 3PL |
| Main costs | Amazon fulfilment and storage fees, plus prep | Your own storage, packing and postage costs |
| Stock prep | Must meet Amazon’s prep rules before sending in | Pack to your own standard |
| Control over stock | Lower: stock sits in Amazon’s network | Higher: stock stays where you can reach it |
| Delivery standards | Amazon’s responsibility | Yours: 90% on-time delivery rate on Amazon.co.uk |
When FBA is the better choice
- Fast-selling, small, light products. Amazon’s fees tend to work best for items that sell quickly and do not sit in storage for long.
- You want the Prime badge without running Prime-level delivery yourself. FBA listings qualify automatically.
- You do not want to handle customer service and returns. Amazon deals with them for FBA orders.
- Amazon is your main sales channel. If most of your sales are on Amazon, keeping stock in its network can be simpler.
Remember that since 1 July 2026, Amazon no longer preps or labels FBA stock in the UK. Every unit must arrive with an FNSKU label, compliant packaging and boxes within Amazon’s limits. Our Amazon FBA prep guide covers the requirements in detail.
When FBM is the better choice
- Slow-moving products. Stock that sells slowly can build up storage costs in Amazon’s network.
- Large, heavy or awkward items. Bulky products such as bedding or large pet food bags can cost more to fulfil through FBA.
- You sell on several channels. One stock pool can serve Amazon, eBay, TikTok Shop and your own website, instead of splitting stock.
- You want control over packaging. FBM lets you use branded boxes and inserts on every order.
The trade-off is performance. Since 16 September 2025, Amazon expects FBM sellers on Amazon.co.uk to keep an on-time delivery rate of at least 90%, alongside its existing late dispatch requirements. Fast, reliable dispatch is not optional.
Seller Fulfilled Prime: the middle option
Seller Fulfilled Prime (SFP) lets you show the Prime badge on orders you or your 3PL ship. To join, you must pass a trial and then keep meeting strict standards on delivery speed, on-time delivery, valid tracking and cancellations. Amazon updates these thresholds from time to time, so check the current UK requirements in Seller Central before you apply.
SFP suits sellers with a fast, dependable fulfilment operation who want Prime visibility without sending stock into Amazon. It does not suit anyone who cannot ship reliably every working day.
Why many UK sellers use both
A hybrid approach often works best. Common set-ups include:
- FBA for best sellers, FBM for the rest. Send fast movers to Amazon and fulfil slower or bulky products yourself.
- FBM as a backup. Keep some stock at your 3PL so you can still sell on Amazon if your FBA stock runs out or inbound shipments are delayed.
- One warehouse feeding everything. Your 3PL holds the main stock, sends regular FBA shipments, and ships FBM, eBay, TikTok Shop and website orders directly.
How a 3PL supports FBA and FBM
A fulfilment partner can handle both sides from one warehouse. At Pro Packers UK, clients deliver stock to our 35,000 sq ft warehouse in Colne, Lancashire, where it is checked in and recorded in our warehouse management system. We prep stock for FBA, including FNSKU labelling, polybagging and bundling, and ship FBM orders with Evri, DPD, FedEx or DX. 92% of our orders are shipped the same day. See our FBA prep centre for Manchester and the North West and ecommerce fulfilment service.
Common mistakes to avoid
- Sending slow-selling stock to FBA and paying to store it for months.
- Switching to FBM without a reliable carrier set-up, then missing Amazon’s 90% on-time delivery rate.
- Keeping all stock in FBA with no backup, so a stockout or inbound delay stops your sales.
- Assuming Amazon will fix prep problems. Since July 2026 it will not.
Frequently asked questions
Is FBA or FBM cheaper in the UK?
It depends on the product. FBA often works out well for small, fast-selling items, while FBM can be cheaper for slow-moving, heavy or bulky products that would build up Amazon storage costs. Compare the full cost per order for each route, including prep, storage and postage.
Can I use FBA and FBM at the same time?
Yes. Many sellers send best sellers to FBA and fulfil other products, or backup stock, through FBM. A 3PL can manage both from one warehouse.
Do FBM orders get the Prime badge?
Only if you join Seller Fulfilled Prime, which requires passing a trial and meeting strict delivery and performance standards.
What delivery standard does Amazon expect for FBM?
Since 16 September 2025, Amazon expects FBM sellers on Amazon.co.uk to keep an on-time delivery rate of at least 90%, as well as meeting late dispatch requirements.
Does Amazon still prep FBA stock in the UK?
No. Amazon stopped offering prep and labelling services for FBA shipments in its UK and European stores on 1 July 2026. Read our FBA prep guide.
Next steps
If you want help running FBA and FBM side by side, request a quote with your products and monthly volumes. You may also find these useful: how much ecommerce fulfilment costs in the UK and how to choose a 3PL in the UK.
