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How to flag duplicate values in Excel and Google Sheets
Topic:Duplicates & uniquenessExcel & Google Sheets
=IF(COUNTIF($A$2:$A$6,A2)>1,"Duplicate","Unique")✓
Verified example
Computed by a real spreadsheet engine on the sample data below.
| Item | Status |
| Apple | |
| Banana | |
| Apple | |
| Cherry | |
| Banana |
=IF(COUNTIF($A$2:$A$6,A2)>1,"Duplicate","Unique")→Duplicate
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Step by step
- 1In a helper column (e.g., B2), enter =IF(COUNTIF($A$2:$A$6,A2)>1,"Duplicate","Unique") — lock the range with $ so it doesn't shift when you copy down.
- 2Copy the formula down through all rows in your data (e.g., B2:B6).
- 3Filter or sort column B to group all 'Duplicate' entries together for easy review or deletion.
Tips
- To flag only the second and subsequent occurrences (keeping the first), use COUNTIF($A$2:A2,A2)>1 with a mixed reference — the first row is absolute, the second is relative so the range expands row by row.
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Frequently asked
Does the formula catch duplicates that differ only in case?
Yes — COUNTIF is case-insensitive, so 'Apple' and 'apple' are treated as the same value.
Can I flag duplicates across two separate columns?
Yes — change the range to cover both columns, e.g. COUNTIF($A$2:$B$6,A2)>1.
More on Duplicates & uniqueness
See all →How-to
How to remove duplicates
Remove duplicate values with one formula using UNIQUE, or strip them in place with the built-in tool. Works in Excel 365 and Google Sheets.
How-toHow to compare two columns
Check whether two columns match row by row, or find values in one column missing from another, using IF and COUNTIF.
How-toHow to get a sorted list of unique values
Extract a sorted, deduplicated list from a column using SORT+UNIQUE in modern Excel and Google Sheets, or array formulas in older versions.
How-toUNIQUE function vs Remove Duplicates in Excel and Sheets
Learn when to use the UNIQUE formula versus the Remove Duplicates tool in Excel and Google Sheets to eliminate or surface distinct values.
How-toHow to find duplicate values
Identify which values appear more than once in a list using COUNTIF to add a Duplicate/Unique label to each row.
How-toHow to compare two lists for differences
Find values that exist in one list but not the other using COUNTIF to label each item as Matched or Unmatched.