Amazon's 250 Character Indexing Maximum

What Amazon’s 250 Character Indexing Maximum Means for Merchants

Update: August 22, 2018: Clarifications About Update to Search Term Field

You bet that Amazon keyword guidelines have changed again. For a full explanation and best practices regarding the new 249-bytes-on-1-line rules, read “Amazon Takes a Byte Out of Search Terms.” We’ll keep this original post active and add rolling updates so that all of the changes are logged for your reference.

Update: August 3, 2018: Seller Central Notification About Update to Search Term Field

Amazon recently added a notification upon logging in to Seller Central to inform sellers about the less than 250 bytes limit to the search term field. This isn’t news to most sellers but it does show that Amazon has officially set the record straight on its site and not in a forum. The notification says:

Amazon limits the length of the search terms attribute to less than 250 bytes. If your search terms exceed the limit, you will now see a warning message beside the search terms field on the Keywords tab in Seller Central.

If you see the warning message, click Save and finish on the same tab. Your search terms within the length limit will be saved. This shortened version is the first 249 bytes of your current terms. You can edit the terms, but they must be less than the limit.

For information on how to optimize your search terms, see Using search terms effectively.

Along with this official update, Amazon has also removed the ability to add multiple search term lines (now just one line instead of five). Included with this update is a nifty notification to let you know that you’ve exceeded the 250 character limit in the single Search Terms field line. The notification says, “Search Terms: Please reduce your generic keyword length to less than 250 bytes.”


Update: August 24, 2017: Seller Central Notification About Quality of Search Results

Amazon posted in Seller Central on August 24, 2017, about a “new feature improving the quality of search results.” Here’s the original message with embolden text of the most important updates:

Amazon launched a feature that limits the length of the generic keywords attribute to less than 200 bytes in India, 500 bytes in Japan and 250 bytes in every other marketplace except China. The limits have been shown to improve the quality of search results. It applies to newly registered and existing ASINs.

Key Guidelines:

  • Keep content within the prescribed length limit (less than 250, 200 for India, 500 for Japan):
    • Length limit applies to total content in all generic keyword fields (a max. of 5 attributes).
    • Whole entry will be rejected upon exceeding limit.
    • Number of bytes equals number of characters for alphanumeric characters (e.g. a-z, 0-9) while other characters can be 2 bytes or more. Examples include ä (2 bytes), £ (2 bytes), € (3 bytes) or ❤ (3 bytes).
    • Spaces and punctuation (“;” “,”, “.”) do not contribute to the length limit, but words should be space-separated. Punctuation between words is unnecessary.
  • Optimising keyword content for search discoverability:
    • Do not include keywords that are not descriptive of the product.
    • Do not include brand names (even your own) or other product identifiers.
    • Do not duplicate content present in other attributes, such as title and bullet points.
    • No need to repeat keywords; once is enough.
    • Use keywords that are synonyms, hypernyms or spelling variations of content in visible attributes (e.g. if product title is ‘whiskey’, use ‘whisky‘ in generic keywords).

For further information, see how to optimize listings for search and browse.

Update: July 20, 2017: Amazon Confirms 250 Character Change

An Amazon Seller Central Support representative posted in a thread about the algorithm/character limit shake up. Here’s the original thread from the forum. You can also read the thread below.

Hello Sellers,

We understand your concern with the input of search keywords. 

Amazon launched a feature that limits the length of the generic keywords attribute to less than 200 bytes in the IN marketplace, 500 bytes in the JP marketplace and 250 bytes in every other marketplace except the CN marketplace. The limits have shown to improve the quality of Search results. To date, the Search team has been suppressing generic keyword attributes that exceed these limits. This will apply to newly registered ASINs as well as existing ASINs.

We recommend following the guidelines below to optimize your use of the generic keywords attribute. 

Key Guidelines for the Generic Keywords Attribute:

Keep the content within the prescribed length limit (less than 250, 200 for IN, 500 for JP):

The length limit applies to the total content in all generic keyword fields (A max of 5 attributes).

The number of bytes equals the number of characters for alphanumeric characters (i.e. a–z, A–Z, 0–9) while other characters, such as umlauts (e.g. ä), each corresponding to 2 bytes or more. Examples of other character byte sizes include £ (2 bytes), € (3 bytes) or ❤ (3 bytes).

Spaces and punctuation (“;” “,” “.”) do not contribute to the length limit, but words should still be separated by spaces. There is no need for punctuation, such as commas, between words.

Guidelines for optimizing keyword content for Search discoverability:

Do not include keywords that are not descriptive of the product.

Do not include brand names (even your own) or other product identifiers.

Do not duplicate content that is present in other attributes, such as title and bullet points.

There is no need to repeat keywords; once is enough.

We recommend using keywords that are synonyms, hypernyms, or spelling variations of content in visible attributes (e.g. if the product title contains ‘whiskey’, the generic keyword attribute may contain spelling variations (‘whisky’); if the product is a ‘guitar’, the generic keywords may contain a hypernym (‘musical instrument’).

For further information, please refer to the optimize listings for search and browse help page . 


I had a question sent to me in a Private Message, and I wanted to make a clarification here. 

The prescribed length limit is less than 250 in ALL markets, except IN, JP and CN. Therefore, the prescribed length limit is less than 250 for the NA marketplaces, .ca, .com, .mx

—End of thread—

Here’s the original thread that prompted us to report on the algorithm/character limit update

Here’s the copy of an email a customer sent us that they received from Amazon support:

Dear Seller,

Thank you for writing back to us and letting us know that the issue has been fixed when the keywords are shortened to no more than 250 characters.

Please be informed that I have contacted our concerned team and received a response stating that as the Search team is constantly working to improve the relevance of search results for our customers. This help our sellers too, since we can remove non-relevant products and let sellers compete with smaller result sets of only relevant items.

Our concerned team is running a project on this to help optimize our approach, and have not yet finalized any communication, but that is still in progress.

As of now this is working as designed, the system ignores any generic keywords over 250 bytes for all the categories including health and personal and beauty. In addition, we were also informed that our system do not do partial matching of Generic Keywords fields and it is unlikely that anyone will search for paragraphs of keywords in their entirety.

AS per the help seller can put 1000 characters but our system can index only 250 characters at maximum.

Please know that we currently do not have an option of indexing the keywords to more than 250 characters. I apologize if this policy doesn’t meet your business needs.

I do understand that this may help you for better buyer experience. However, at this time, this feature is not available for our sellers.

As to make sure that you are heard, I have passed your message to the Business team as a feedback, so they are aware of your interest.

As we continue to improve both our platform and our service, input from Sellers like you is valuable. I truly appreciate your suggestion as this is a great input for Amazon to work upon and this can actually be of great help to Sellers as well as Buyers.

If there are changes pertaining to this, Sellers will be notified via Seller Central. We encourage you to keep checking, as functionality is often refined over time.

We strive to make your selling experience on Amazon as eventful as possible and therefore we are willing to extend any help that you may need at any time.

I personally wish I was able to do a lot more in this regard however, as the Policies are determined by our Business team we at Seller Support would not be able to influence those decisions.

We wish you great success in your future endeavors. Have a wonderful day!

What Amazon’s 250 character indexing maximum means

It seems Amazon will now only index the first 250 characters in a product detail page’s backend keywords instead of 5,000 characters as believed before. This applies to all five search term fields. The biggest points of this update are:

  1. Generic keywords will be normalized, which means all upper and lower case keywords, and singular and plural forms of the same keyword, shouldn’t be added.
  2. Merchants don’t need to add keywords that already appear in the title, description and subject keywords.
  3. Amazon’s system ignores any generic keywords beyond 250 characters for every category.
  4. Amazon will also discontinue doing partial matching of generic keyword fields because it believes it is unlikely anybody will search for paragraphs of keywords.

This means Amazon third-party merchants will need to be extremely cognizant of the keywords they use in their product detail pages. To give you some context, 250 characters is about 40 words, which isn’t a lot. So keyword research and optimization will be more crucial than ever to stand out in organic search.

How to know if your product is indexed for a specific keyword

There are a couple of ways you can discover if your product or a competitor’s product is indexed for a specific keyword. This process is known as a reverse ASIN lookup. The first method is a bit manual.

Manual Reverse ASIN Lookup

First, go to the product detail page if you don’t have the ASIN on hand. Once you land on the page, go to the URL and locate the 10-digit ASIN. For our example, we’ll use our steadfast apple slicer; it’s ASIN is B00XTCERLE.


Now, go to the search bar and paste in your ASIN and add a ‘+’ then the keyword you want to check whether it’s indexed or not. If I want to know whether or not the apple slicer is indexed for the keyword slicer, I would simply put B00XTCERLE+slicer into the search bar and hit enter. If the ASIN is indexed for this keyword, it will then be displayed on the search engine results page. If it isn’t indexed, say for example I search for B00XTCERLE+manzana, the search engine results page will say “Your search “B00XTCERLE+manzana” did not match any products.”

You can use this reverse ASIN lookup method on any product on Amazon. But it’s a manual process that only verifies if a product is indexed for a keyword—it doesn’t give you any new keywords.

Reverse ASIN Lookup with Scope

If you want to sophisticate your reverse ASIN lookup process, then use our Scope tool.

First, go to the product detail page you want to research. For this example, I’ll be using the apple slicer, again. Select Show Scope from the bottom right-hand corner on Amazon. Scope shows 217 keywords for the apple slicer ASIN in a variety of long-tail formats. You can view the results based on the keyword, time it was last refreshed, search volume, CPC bid, search position and estimated sales. We can narrow down the results for search volume since we want to see what shoppers are mostly looking for. We can then export the keywords to a .csv file to remove any duplicates.

This process will show you which keywords you or your competitors are ranking for, and it will give you a starting place to begin your backend keyword optimization process.

Moving Forward

This update is a positive step forward for merchants, shoppers and Amazon. Why? Because it means Amazon search will produce much more relevant results. The biggest challenge for merchants is that they’ll have to spend more time optimizing keywords for both organic and paid search. The result should be lower impressions but higher conversions because shoppers are landing on relevant search engine results pages.

And if you’re looking to take your brand and reputation on Amazon to the next level, you need automated Buyer-Seller messaging!

Save time, build your brand and improve your reputation with Feedback Genius. Every new account gets a free 30-day trial.




Jeff Cohen

Jeff has more than 15 years of e-commerce experience. Currently, he is CMO and Partner at Seller Labs where he works with more than 20,000 Amazon sellers providing software solutions and expert advice. He's also an International speaker and is widely regarded as an industry expert who is asked to share actionable intelligence on how Amazon works and how sellers can improve their business.

This Post Has 68 Comments
  1. Does this mean 250 Keywords per each of the 5 lines, for a total of 1,250 key words? Or a total of 250 keywords can only be used between all 5 lines?

      1. 250 characters per line? Or 250 characters total for the backend (50 characters per line)? Also, should keywords be separated by commas? Do commas count as a character? And should keywords be in a logical order or does order not matter?

        1. 250 total – can all be in first line and leave others blank). No commas – just separate with a space which doesn’t count in the 250 (thank goodness!)
          And logical order does not seem to matter – but prob best to put your more important ones at the beginning.
          At least that’s what I’ve found.

  2. I’m seeing conflicting information in various places and was hoping someone can help me with this. Should the Product Name, Bullets and Description be based broadly around keywords or should keywords be together like in keyphrases? For example, does “lunch bag” need to be together as in a keyphrase or can it be more broad like “best bag for lunch”?

  3. If we currently have all 5,000 characters used up in 5 lines, do you think Amazon indexes the FIRST 250 chars. of the first line, and skips the rest?

  4. So do we add the keywords we are ranking for and the ones our competitors are ranking for into our backend search terms on Amazon?

  5. 250 characters total in the backend, not including spaces. You can put them all in the first line, no commas, just a space between each word, and they can be in any order, you do not need to enter them as phrases. Be careful if you add another keyword later on — once you go over 250 everything except title stops indexing. Use whatever keywords you don’t already have in the title and bullets.
    I am the customer who got that reply from seller support shown in this article. After much trial and error they finally figured out that the new rule is 250 characters. And although Amazon says that you “can” enter 1,000, my testing shows that is not true. More than 250 don’t get indexed, and more than 250 prevents the first 250, and the bullets, from being indexed.
    Please test with your accounts. Copy your current keyword list to a text doc to save, delete everything, and then pick out best keywords to max of 250 characters. Let them populate for at least 15 minutes then check for indexing.

    1. So you are saying that if you exceed the 250 character limit in the backend keyword fields this will trigger Amazon to suppress indexing the words in your bullet points? Im curious how you came to this conclusion?

      1. Once I went over 250 characters, when I checked my ASIN plus some keywords that were in the bullets, it showed 0 results. I checked with various keywords from the bullets. No indexing. Once I got back to max 250 everything in the bullets indexed again.

        1. Hmmm… Thats interesting. I’ll have to do some testing and get my listing into shape with the new guidelines. Thanks for sharing this information with all of us!

    2. Please explain “Amazon will also discontinue doing partial matching of generic keyword fields because it believes it is unlikely anybody will search for paragraphs of keywords”

  6. Does this “only” effect generic keywords? My Amazon upload template also has the following fields “target_audience_keywords1-3” and “thesaurus_subject_keywords1-3”. The template limits these to fifty characters each (including spaces) for a total of 300 characters. I use the Amazon generated product upload templates to generate all my listings so I should be able to make changes quickly once I have a clear idea how to proceed. Thanks for the info.

    1. Different people have different philosophies on this. I like to fill out every logical field on my listing that I can. just make sure it makes sense.

  7. Really guys? You are writing articles now based on 1 persons reply from Seller Support? I think every seller knows that Seller Support is retarded. I just asked Seller Support and they told me input field is 5000 characters…. What now? Maybe do some research, or at least we an official statement from Amazon before posting.

    1. What the rep told you is true. The input field is 5000 characters. Did you ask with the field is or how many they index. I agree that seller support will give different answers. As a seller you are welcome to do what you want. We are just making a suggestion for optimization.

  8. I think we’re all trying to draw too many conclusions with too little evidence. I have 1000 characters in each of my 5 KW fields, and upon checking, I am indexed for about 80-85% of those keywords. This is true for all of my products (not just one).
    According to the ‘theory’ presented here, I should not be indexed for most of the KWs in my backend … but I am … so how do you explain that?
    Let’s also remember that this article was written to promote their KW indexing tool, so don’t be too quick to embrace what has been said as fact. It clearly is not! 🙁

    1. Jup, here is what I got from Seller Support:

      “This is Adrian, and I am the associate that has taken over this case. I understand you are wanting some clarification on how Amazon uses the indexing characters for the “Search Terms” field, and I’ll be able to shed some light on this matter.

      During my investigation of how “Search Terms” are used and how many characters are used in each field, I was able to find that Amazon does account for all 1000 characters used within the text field.

      These search terms should be limited to terms not currently used within the Title of your product or in the Bullet Point fields found in the products Details Page. “

    2. For you to really dig into that you also need to verify the that characters on the 5kw fields are not in your title, bullets or descriptions. Amazon still uses these fields to index your listing.

  9. I normally searched “ASIN keyword” instead of “ASIN+keyword” to see whether my listing shows for respective keyword and it worked too. So why is “+” necessary if it can work without?

  10. I can confirm the 250 character limit on our end. We had around 2000 characters for each of our products but most of our keywords were not indexed. After cutting it to 250, all of our keywords were indexed. So I decided to readd some to around 280 characters and again, many keywords weren’t indexed so I’m really not sure what this is based on and if it only applies to some accounts/products and not all.

  11. Hi, I am confused of how we can put on the backend keywords

    Especially for this one:
    Merchants don’t need to add keywords that already appear in the title, description and subject keywords.

    If there is the case, that means we need to dig deeper for keywords from bullet point or reliable source.

    Does it means we need to focus on the Synonym of those keywords from the title, description and subject keywords?

    1. Adding a keyword in multiple places doesn’t increase the likelihood of it being indexed. If you have “apple slicer” in the title, you don’t need it on the backend. Synonyms is a good idea, maybe a foreign language terms or an alternative use. IF you can use the apple slicer to also cut a different fruit, add it. But if it won’t cut a pineapple, don’t add that term.

  12. If you test what’s written here with your own keywords from your own seller central account, and see what is and isn’t indexing, this post is just completely wrong. I have words indexing that are way outside of the supposed “250 character limit” while the very first words in the keyword lines are not indexing at all. It’s frustrating when this is posted without much actual testing – just one email from an Amazon agent that clearly isn’t from their US office – where algorithmic decisions are probably made. At the end of the day, sometimes Amazon employees seem to make stuff up to simply close a case, sound smart, or any number of other human reasons for giving whatever answer is likely to allow them to get on with the rest of their day.

    1. So we know for a fact that the order of the keywords in the backend doesn’t affect indexing. Amazon will randomly pick. Also, if your backend keywords are also in your product detail page, they will index. Amazon isn’t only indexing 250 characters. they index your title, bullets, description and your back end keywords.

      Many sellers have stuffed the backend with irrelevant keywords. That is why Amazon has been changing how it reads and interrupts this data.

      1. From my testing using ‘ASIN’+keyword in the search bar they do not index keywords that only appear in the description.

        1. I have not tested descriptions, but regardless of what the documentation says, I would be SHOCKED if they index descriptions. It makes no sense and goes against any normal idea of a search schema that makes sense. If I have a USB drive and say in my description, “And you can plug it into your Blu-ray player to play back MP3 files.”.

          Will my USB drive now index and show up in a search for Blu-ray players?

          The description is so full of noise that it doesn’t make sense to index, even if you apply weight to the different fields and give the description the lowest score.

    1. We looked at listings and indexed keywords. We then got the letter from an Amazon support person. We don’t believe that any of this is absolute. The 250 character limit could change to 500 or back t0 5000 tomorrow.

      I think the point that you should take home is that keyword stuffing on backend keywords doesn’t work any more. Make sure your terms are relevant to your product.

  13. Please explain “Amazon will also discontinue doing partial matching of generic keyword fields because it believes it is unlikely anybody will search for paragraphs of keywords.”

    1. Amazon is moving for “vector” search. This allows them to know that a car is also an automobile even if you don’t enter both terms. if someone was to search for “getting around town” it could relate that term to a car as well.

      Amazon doesn’t look for keywords or phrases in the order that you enter them. so a red wagon is also “wagon red”.

      On the front end make sure your keywords are logical to the reader.

  14. I have lost a lot of respect for Jeff and his company with this article. First there are a lot of obvious holes in the idea that Amazon is only using 5% of the space they provide merchants, as well too many vendors are indexed for thousands of characters not 250. Lastly and I won’t spend any more time helping this post with good content, but Jeff doesn’t care enough to engage in answering comments. Seller labs is like all the old SEO companies of years past only concerned with his over priced tools and seminars in Mexico for $5,000. Take everything these self proclaimed gurus say as the blind leading the blind.

    1. Thank you for your comment Mr Best. I am not sure what overpriced Seminar you are discussing, all of our content and webinars are free. We do have one conference on an annual basis that we charge for, it was $499 and was located in Atlanta, GA.

      You are welcome to challenge our assumptions in this post. Just make sure you have your facts straight.

      1. Oh wow a response! This article needs follow up and further research is my point. I apologies if it’s not your group doing over priced Mexico getaways. For the record I actually heard good things about your mastermind a couple months back in GA. However my point still stands there are too many philosophies for rankings on Amazon and not enough proof of the techniques successfully used. You have many important questions from readers raised as a result of this article.. lets try and address those as the “guru”. Or try a podcast or post with content from actual sellers ranking on Amazon not from from those selling over priced wares and webinars.

  15. When writing the Keywords in phrases for example rideon cars for kids, 12v kids ride on car, ride on for 2 kid. Do you repeat the words? how would you write it?

  16. Thanks for this. When you say: “Merchants don’t need to add keywords that already appear in the title, description and subject keywords.”, what are the subject keywords? Has that function been removed now? Also do you include bullet points in the above? I.e. we don’t need to add keywords that already appear in the title bullets and description?

    1. as far as we can tell at this point in time it is not indexed but that doesn’t mean that will change in the future.

    1. Based off of what Amazon says, no. Do not duplicate content present in other attributes, such as title and bullet points.


    Our SVS rep very specifically told us that including any more than 249 means NOTHING will be indexed!!!

  18. So I am using an Amazon template to upload products that has 12 different fields for keywords. They are specific uses keywords 1-5, target audience keywords 1-3, thesaurus subject keywords 1-3, and last generic_keywords. Some of them will limit you to 50 characters some not. Is this 250 character limit only on the generic keywords? I upload and update products using exel files and this is pretty common no matter what category I am uploading to. Any thoughts.

  19. I’m unsure whether it’s best to update the back end keywords yet, as I’m still showing as indexing for way more than 250 characters! Last time I checked I had over 500 characters of words that are all still indexing. That’s just for one product…
    I have a feeling that if i start messing with it, I’ll then index for less keywords.
    Could it hurt us for not updating?!

  20. is it matters if all the keywords placed in one field, the first field, or divided to all the 5 fields
    , like 50 in each ?

  21. I also wonder: was told 250 was the max (actually, someone at Amazon just told me 500 is the max!) but I’m confused as to whether this can be all in one line, or if it needs to be parsed among 5 lines. In Europe, it has to be among 5 lines (again, Amazon told me that, but that doesn’t mean it’s actually true). Does anyone have firm information about this?

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