The Search Terms field in Seller Central has a built-in byte counter which stops accepting input at the length limit that is quoted in bytes and not characters as some Search Terms contain multi-byte characters.
Bytes correspond to 1:1 for alphanumeric characters (for example a – z, A - Z, 0 - 9). The length becomes variable when dealing with more complex characters such as umlauts in German (for example ä), which can be 2 bytes per character. Other complex characters, such as Japanese and Chinese characters can be 3 or 4 bytes. There are cases where Search Terms can contain a mixture of single and multi-byte characters, which make prediction of character count complex.
No. For the purpose of calculating the length of Search Terms, Amazon Search does not count spaces or punctuation. For readability, Search Terms should be separated by spaces. Punctuation can be used, but is not mandatory.
The Search Terms field was reduced from five fields to one field to improve the quality of Amazon Search results. Previously, it was possible to add up to 5,000 bytes worth of Search Terms but it generated a lot of spam (irrelevant Search Terms).The reduced quota of Search Terms helps sellers focus on only using relevant words to describe specific products.
To facilitate this change, the content of all Search Terms fields was combined into the first field. Sellers were asked to click "Save and Finish,” in order to overwrite the content and be within the length limit. Sellers were allowed to edit the content before hitting Save. Once saved, any excess was gone.
If Search Terms are over the limit, none of the Search Terms for that ASIN will be indexed by Amazon Search. Being indexed means that your ASIN is eligible (but not guaranteed) to appear in search results for matching Search Terms.
If the "Category Listing Report" option is enabled under the Inventory tab in your Seller Central account, you can download a spreadsheet of the existing listings. If it is not enabled, you can ask Seller Support to enable that option in your account. Once you've downloaded your current listings, you can use an Inventory file template to perform bulk upload changes using the "partial update" function.
Amazon determines the relevancy of search terms using a machine learning model. The terms we deem relevant may change over time as Amazon's machine-learning model continuously gathers data. This is an automated process and Amazon reserves the right not to use all supplied keywords for retrieving products.