Amazon title, Highlights & backend byte checker
Counts the 75-character Item name and the 125-character Item Highlights in code, counts the backend generic-keyword field in bytes rather than characters, and flags the Highlights lock that most catalogue audits miss entirely.
What the lock actually costs
Amazon confirmed Item Highlights is disabled until the Item name is at or below 75 characters. That is Seller Central's own interface message rather than an inference. The consequence is not proportional and it catches people out.
Sellers attempting to populate Item Highlights on an over-limit listing report Seller Central returning error code 100476:
“Provide an Item Name that is 75 characters or less to use Item Highlights.”
The field sits under Manage All Inventory → Edit listing → Product Details, and some sellers first encountered it through the AI “View Enhancements” panel, where the item name and item highlights appear together.
Two things to hold alongside the lock. The field is behaving inconsistently: sellers report entering Highlights, returning 24 hours later and finding the original recommended text restored, and an Amazon forum moderator has acknowledged that “some sellers are currently experiencing system errors or changes not saving.” Observed
And the dependency is disputed. SellerSprite argues Item Highlights is an independent attribute that should be populated regardless of title length, describing the lock as widely reported but not confirmed by Amazon in writing. The error code above is the strongest evidence for the lock and we treat it as decisive — but the disagreement is real, and if you are about to make this claim to a client, verify it in that account first. Contested
A listing at 74 characters has 199 characters of indexed, seller-controlled, top-of-page text. A listing at 76 characters has 76. That is why a catalogue audit reporting “average title length” understates the loss. The number that moves a decision is how many ASINs currently have Item Highlights locked, and how many indexed characters that forfeits in total.
Spaces count. Trailing whitespace counts, and pasted spreadsheet cells carry it. Non-ASCII characters cost two to four bytes each in the byte-limited backend field. Every count in a migration should be produced in code and checked before upload.
Bytes, not characters
Amazon confirmed The backend generic-keywords field is limited in bytes. ASCII characters take one byte; accented and special characters take two to four. Amazon's own announcement describes terms over the limit being saved as the first 249 bytes.
Amazon confirmed Separately, a widely repeated claim holds that an overrun makes Amazon discard the entire field silently. Amazon’s own moderator wording says otherwise — terms past the limit are not saved, and a warning appears beside the field. We could find no credible evidence for wholesale discard and no longer repeat it. The real risk is duller: bytes are not characters, and anything past roughly 249 bytes never gets indexed.
Where each displaced term should go
Shortening a title without re-homing its terms is how a catalogue loses queries it had already earned. The full placement hierarchy, the migration sequence and the two-week orphan check are on the 75/125 title system page.
Counting is the easy part
A migration across a full catalogue means term inventories, attribute sequencing, an orphan check at two weeks and a verdict at six. Get the four biggest leaks in your account named in 72 hours instead.
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