When is this useful?
It is useful as a pre-import check for keys that should appear only once. Finding duplicate order IDs before an upload is much easier than diagnosing a rejected batch afterward.
Free web tool
Check uniqueness of a CSV key column and list duplicate keys with row numbers.
Use this when one selected column—such as product ID, order ID, or membership number—should be unique. The result shows duplicate keys and the CSV row numbers where they appear.
It is useful as a pre-import check for keys that should appear only once. Finding duplicate order IDs before an upload is much easier than diagnosing a rejected batch afterward.
The selected cell value is compared as-is. The tool does not automatically trim spaces or normalize case. That means ABC and abc, or A001 and A001 , are different keys unless you normalize them first.
If SKU A-102 appears on rows 12, 48, and 51, inspect those rows first. They may be accidental duplicates—or separate stores may legitimately reuse the same SKU, which means SKU alone was the wrong uniqueness rule.
The “duplicate keys” metric counts distinct key values that occur more than once, not the number of duplicate rows. One key repeated ten times is still one duplicate key. Use the row-number list to see how many records share it.