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How to Find Duplicates in Excel

Finding duplicates - seeing which values repeat and how often - is different from deleting them. Here's how to highlight and count duplicates online in seconds, plus the classic Conditional Formatting and COUNTIF methods.

Use the online tool

The fastest option is available in your browser with no upload to a server.

Find Duplicates Online

Steps

  1. Open the free online finder - Drop your .xlsx, .xls, .xlsm, .xlsb, or .csv file into the browser-based finder - nothing is uploaded to a server.
  2. Pick what counts as a duplicate - Match on the whole row, or choose key columns like email or ID so rows are compared on just those fields.
  3. Review highlights and counts - Duplicate rows are flagged and counted, with first occurrences and repeats shaded differently, so you can see the scale before changing anything.
  4. Export or clean up - Download just the duplicates (with counts) or an annotated copy, then use the Remove Duplicates tool if you want to delete them.

Before You Start

  • Finding duplicates never changes your file - it only reports. Deleting is a separate, deliberate step.
  • Turn on 'Ignore case' and 'Ignore extra spaces' so 'ACME' and ' acme ' are treated as the same value.
  • Matching on a key column (like email) catches duplicates even when other columns differ.

Alternative Methods

  • Conditional Formatting (highlight in Excel) - Select the range, then Home > Conditional Formatting > Highlight Cells Rules > Duplicate Values. Fast to see duplicates in a single column, but it works per-cell, not per-row.
  • COUNTIF formula - Add a helper column with =COUNTIF(A:A, A2) - any result greater than 1 is a duplicate. Use =COUNTIFS(...) to check duplicates across several columns.
  • Remove Duplicates (delete) - Data > Remove Duplicates deletes repeats immediately. Use it only after you've reviewed what will be removed - or use the online finder first.

Frequently Asked Questions