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This article applies to selling in: United Kingdom

Clothing size standards FAQ

At a high level, what has changed?

Amazon standardised clothing size inputs to facilitate a more consistent customer experience. Seller contributions containing clothing size that does not follow the guidelines of the store will be re-formatted to Amazon standard sizing. If a contribution is not visible due to an invalid clothing size, you will need to re-submit the contribution with a valid UK clothing size to make the sizes visible.

Why is Amazon now enforcing the clothing size guidelines?

Amazon believes that customers are entitled to shop in sizes that they understand. Unintelligible sizes clutter the size drop-down and lead to duplicate products. In addition, products with clean sizes are discoverable via size-specific browse refinements and show better sales conversion compared to products with size defects. Amazon is committed to helping sellers meet this data quality bar by providing detailed guidelines during all steps of the listing process.

How does this benefit my business?

Standardised sizing improves the customer’s shopping discovery and purchasing experience. We found that ASINs with a valid size name had a higher percentage of Glance Views (the number of times a detail page is viewed) compared to ASINs with non-valid size names. We observed a similar trend with regards to Ordered Product Sales (OPS).

What are the customer benefits of standardised clothing sizes?

Only the sizes that a customer is familiar with based on geographical location will appear in the clothing size drop-down. In addition, when browsing on Amazon, customers will find that additional selection is now available when filtering search results using the left-hand navigation tools. For example, previously when you selected options such as clothing size, only a limited number of results appeared. With Amazon’s standardisation of clothing size, customers will be able to easily find the exact clothing that they are looking for within Amazon’s vast selection.

How will the listing creation experience change?

Instead of providing an clothing size with free-form text through the size_name attribute, Amazon will provide a series of values to guide sellers to provide standardised sizes for each attribute. For example, an attribute may require you to designate if the clothing size is for an Adult or Toddler (under the Age Range Description attribute). Based on the selected option, the later attributes will consolidate to a limited list of applicable values. For more information, go to Clothing Product Listing Experience. These changes are applicable across all listing experiences (custom templates, feeds, 1 by 1).

When will the listing experience change go into effect?

All new ASIN listings and updates on existing ASINs must conform to the new attributes. We enforced all the new clothing size attributes beginning February 2021 across the following product types:


What will happen to the values I entered in size_name and variation themes for existing ASINs?

The attribute size_name will remain in the Amazon catalogue, but will not be available in listing experiences after new attributes are enforced. Amazon will automatically combine values from the new attributes to populate the size_name attribute. After enforcement, there is no change in values for variation themes. There is no need to resubmit size_name values if the values for existing ASINs in size_name are valid. For more information, go to Clothing Size Standards.

What are the acceptable clothing sizes for each store?

For a comprehensive list of valid values for clothing size values displayed on the website, go to Clothing Product Listing Experience.

What if I use a feeds integrator?

The same standards will apply to the feed ingestion method. Therefore, if you use a feeds integrator, the integrator will need to conform to the attribute listing standards. Amazon has published these standards approximately 60 days prior to enforcing the new attributes to allow sufficient time to adopt the new standards.

Will the sizes that appear on detail pages match the manufacturer size?

The Amazon-valid sizes are designed to accommodate most sizes in the United Kingdom . If the manufacturer size is different, sellers are expected to convert the manufacturer size to an equivalent size from the valid sizes. It is highly recommended that you submit a size chart so customers can view your clothing size conversion. If you would like to show an clothing size conversion, you can submit a size chart by following these Brand-specific size charts. Size charts are displayed when a customer clicks the size chart link on the detail page.

What if my product size is not an option or falls under an additional attribute?

First, verify that you have selected accurate values for Target Gender, Age Range Description and Size Class attributes as these will determine the values available under subsequent attributes. To provide additional sizing information, consider using sizing charts to give customers more context around product-specific sizing. If you feel that you have a valid use-case where your size is not an available option, you can submit a request to Amazon Selling Partner Support. Amazon will process and consider your request; however, certain requests such as submitting a request to add 28 UK to the US list of valid values will not be acceptable.

What are normalisation rules and why do they exist?

Normalisation rules automatically reformat size values when possible. To make things easier for sellers, we apply normalisation rules to sizes that do not conform to our size format standard to disambiguate sizing for the end customer and eliminate duplicates. For example, if you have previously submitted the clothing size Small or Medium to Amazon’s UK store, it has been automatically converted to S or M.

I noticed my size and sort order changed; why is this?

To improve the customer experience within the clothing size drop-down on Detail pages, Amazon will update the sorting algorithm used on the drop-down. The new sorting logic for clothing sizes was deployed on June 30, 2020 in the UK stores.

Why is the clothing size displayed on the website different from the size information I submitted?

To improve the customer experience, Amazon standardises clothing sizes displayed on our website to eliminate duplicate sizes and standardise the way that sizes are displayed. Having accurate clothing size information and a clean detail page helps build customer confidence and increases conversion. Here is how the clothing size standards work:

If two sellers have listings for the same size and style of men’s clothing but each provides a different size value for that clothing, one being 10 UK and the other 10 , Amazon’s clothing size standardisation logic will convert both sizes to 10 . As a result, only one version of the clothing size 10 will be listed in the size drop-down, and both seller’s offers will be associated with the size 10 clothing.

Is it possible to convert the sizes to display a different country standard (for example, US sizes in the United Kingdom)?

Only the sizes local to the store you are shopping in are displayed in the clothing size drop-down. For example, in the US, a customer will view US sizes; in the United Kingdom, a customer will view UK sizes. If you would like to display an clothing size conversion, you can submit a size chart by following Brand-specific size charts. Size charts are displayed when a customer clicks on the size chart link on the detail page.

Why is my size hidden from the detail page?

In order to improve the customer experience, Amazon retains the right to remove sizes which appear inaccurate or incorrectly formatted. If a size does not follow the size standards listed in the Clothing Size Standards page, it will be subject to removal.

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