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Understanding FBA size limits and how they impact your Amazon arbitrage business

Posted Category Training Tags Strategy

Selling on Amazon FBA can present online arbitrageurs with a number of problems, not least of which is trying to figure out exactly what you’ll pay to Amazon in fulfilment and storage fees. However, a lot of this information is actually quite readily available, and in this article we’re going to look specifically at Amazon FBA size tiers and how they impact your online arbitrage business. Understanding these size tiers and the associated storage costs can mean the difference between profitably arbitraging an item, and losing money.

Additionally, we go through FBA’s packaging requirements and how this impacts size tiers – you might think you’re doing your customer a favour by padding an item more generously than you might otherwise have done, but if it pushes you into a higher size tier, then it might end up costing you.


The complete guide to Amazon FBA size tiers

Amazon FBA size tiers are designed to categorise products based on their dimensions and weight. The reason for this is to determine how much is charged in fulfilment fees. Amazon has a number of different size tiers, which we’ve detailed below.

Small Standard-Size

Dimensions: Items measuring 15 inches long or less, 12 inches wide or less, and 0.75 inches high or less

Weight: Weighing 12oz or less


Large Standard-Size

Dimensions: Items measuring 18 inches long or less, 14 inches wide or less and 8 inches high or less

Weight: Weighing more than 12oz but less than or equal to 20lbs


Small Oversize

Dimensions: Items measuring more than 18 inches but less than or equal to 60 inches long and with a girth of no more than 130 inches

Weight: Weighing more than 20lbs but less than or equal to 70lbs


Medium Oversize

Dimensions: Items measuring more than 60 inches but less than or equal to 108 inches long, and with a girth that exceeds 130 inches but is less than or equal to 165 inches

Weight: Weighing more than 70lbs but less than or equal to 150lbs


Large Oversize

Dimensions: Items measuring more than 108 inches long or with a girth exceeding 165 inches.

Weight: Weighing more than 150lbs


Special Oversize

Dimensions and Weight: Any item that exceeds the large oversize dimensions or weight limits, typically requiring special handling and delivery arrangements


We’ve not listed exact fulfilment fees here because they change quite frequently and it’s likely that whatever was correct at the time of publishing might be out of date within a few weeks or months. You’ll be able to see all fees relevant to the products you have in stock with Amazon within the Seller Central dashboard.

Be aware that for light items that take up a lot of physical space, you will usually be charged by volumetric weight rather than the actual weight. For example, if you had an item that was 200 inches by 30 inches, and weighed 15lbs, you wouldn’t get away with paying for a Large Standard-Size – you’d be paying for Special Oversize which would be a lot more expensive.


How item size impacts storage fees

Amazon charges storage fees to use its warehouse space and this is based on a number of factors – the time of year, how long the inventory has been stored with Amazon but also how large the item is. Each size tier has a different fee structure which also takes into account these other factors, but the general rule is the larger the item, the higher the fee.

Storage fees can become very expensive and can massively eat into your arbitrage profit margins, so it’s very important that you optimise packaging so that your items are as small as possible, as well as regularly auditing your inventory, reviewing what is selling quickly so it can justify the storage fees as well as what isn’t selling and needs to be liquidated for a lower margin.

Amazon increases storage fees around peak periods such as Black Friday and Prime Day, so you should also ensure that you plan for these increases in both your inventory flow and your profit margins.


FBA Packaging Requirements

Size limits aren’t the only thing you need to consider before sending items to an Amazon fulfilment center – Amazon are very picky on their packaging requirements and if you don’t get everything exactly right, you can find that your items won’t even be accepted by an Amazon fulfilment center.

Now, we’ve written previously on why you might want to use an FBA prep center to do this for you, but it’s perfectly possible to do it yourself. Just don’t do what rookie arbitrageurs do and send your inventory direct from the retailer to Amazon – you’ll more than likely find most retailers will refuse to do this, but even for those that will, your items won’t be accepted by Amazon as they won’t be correctly packaged.

A prep center is an invaluable tool in the online arbitrageur’s arsenal – but maybe not quite as invaluable as a product sourcing tool, like SourceMogul. SourceMogul scans hundreds of retailers for thousands of products in order to find you the best online arbitrage opportunities. It shows you the product’s sales rank, the ability to see what your profit will be after Amazon fees and any other associated overheads and also provides a hugely helpful wholesale sourcing option if this is more your thing. We’re offering a free 7 day trial of SourceMogul, which you can access using the link below:

You can find a full run-down of all the rules and regulations within Seller Central, but as a general rule you must use a new, durable, six-sided box to package your items. Poly bags can be used for soft items such as clothing, but they must have a barcode that can be scanned through the bag. Use appropriate packaging material inside the box – don’t use non-recyclable materials like packing peanuts or glitter.

Make sure your items are labelled properly – sometimes Amazon will offer to do this for you for a fee. Each item must have a scannable barcode, and fragile items should be wrapped individually in bubble wrap. If you’re shipping perishables these should be clearly labelled with an expiration date.

If your items are oversize they may need to be palletized – but check with Amazon before you ship if you think this might apply to you. Be aware that this is not an exhaustive list, but should point you in the right direction when it comes to shipping your items to Amazon FBA.


What happens if you don’t comply with Amazon’s size limits or packaging requirements?

Compliance with size limits isn’t really a thing – as long as you’ve packaged your item correctly, Amazon will just categorise your items into a size tier and will charge you accordingly. However, non-compliance with packaging requirements is something that causes problems for lots of online arbitrageurs.

By far the most common thing for sellers not complying with Amazon’s packaging requirements is simply that their inventory gets refused at the door. Amazon won’t accept the delivery, leading you to organise shipping back to you at your expense. Amazon may even give you the option to dispose of or donate the inventory.

If you are found to be in consistent non-compliance with Amazon’s packaging policies, Amazon might even stop you sending any future shipments to their fulfilment centers. It can also negatively impact your seller performance, reducing your likelihood of winning the buy box, as well as significant delays in processing if Amazon does decide to repackage and prep your goods accordingly. You will also get charged for this if this is a decision Amazon makes – but by far the most likely is that they will simply get refused. Amazon puts these policies in place due to how busy their fulfilment centers are and they generally do not have time to repackage and prep your items for you.

By far the best thing you can do to avoid packaging or size limit issues is to use an FBA prep center. While they do represent a cost, it represents massive peace of mind for your online arbitrage business and one we’d thoroughly recommend.


Frequently asked questions

Do size tiers change often?

No. Amazon will, however, change fulfilment and storage fees fairly often. Storage fees change based on how long your items have been with Amazon, but will also change based on the season. You’ll pay more to store an item in November because of Black Friday than you will in February.

You should also keep an eye on periodic storage and fulfilment fee reviews, as these can impact your profitability if you don’t take them into account. You’ll generally be informed via Seller Central when fees are changing, and it’s important to factor these into your margins to ensure you’re still selling profitably.


What happens if I misclassify an item’s size tier?

If you’ve given an item the wrong size tier, when Amazon finds out they will simply reclassify it and adjust their fees accordingly. They may also charge you a fee to reclassify the item. Higher fees mean higher fulfilment costs and lower margins, so it’s in your best interest to make sure you get the size tier right when shipping your items to Amazon.


Can the size tier of my items change over time?

Yes – if Amazon decides to re-measure your product and they find the declared size tier is incorrect, they can reclassify it into a higher size tier.


How best to handle products that are close to a size tier threshold?

Carefully package these items – you need to make sure they’re packaged properly but don’t over-package them so as to send them into another size tier. You should also leave a margin for error in your calculations to give yourself a bit of breathing space and account for any discrepancies.