To identify duplicates in Excel, here are common methods:

1. Using Conditional Formatting:

• Select the range or column where you want to find duplicates.
• Go to the Home tab, click Conditional Formatting > Highlight Cells Rules > Duplicate Values.
• Choose a formatting style and click OK. Duplicates will be highlighted immediately.

2. Using a Formula (COUNTIF):

• Use the formula =COUNTIF(A:A, A2)>1 in a helper column to get TRUE for duplicates and FALSE for unique values.
• To label them, use: =IF(COUNTIF($A$2:$A$100, A2)>1, "Duplicate", "Unique").
• This works within a specific range and can be adjusted accordingly.

3. Finding Duplicate Rows with Multiple Columns:

• Concatenate the values from multiple columns in a helper column: =CONCAT(A2:C2).
• Then apply a COUNTIF or COUNTIFS to find duplicates based on this concatenation.

4. Filtering:

• After marking duplicates with a formula or conditional formatting, use Excel’s filter feature to show only duplicates or unique values.

These methods allow easy identification and management of duplicate data in Excel spreadsheets, whether for single columns or entire rows with multiple columns.