Level: Basic
Duplicate keywords are one of the most common, most avoidable sources of skewed analysis in a keyword research spreadsheet.
The Excel Technique
Select your keyword column, go to Data > Remove Duplicates, and confirm the column range. Excel will remove exact duplicate rows and tell you how many were found. For a quick manual check first, a COUNTIF formula like =COUNTIF(A:A,A2)>1 flagged next to each row shows you which entries are duplicated before you commit to deleting anything.
Example Scenario
You've merged keyword exports from two different research tools into one sheet of 2,400 rows. Before running any volume or competition analysis, you check for duplicates and find over 300 exact repeats that would have inflated your totals if left in.
Where This Fits in Your Keyword Research Process
Deduplication should happen before, not after, any pivot table or aggregate formula — cleaning up after the fact means redoing every downstream calculation.
Next step: Use Remove Duplicates (Exact) from SeoWolf's Notepad to run your combined 2,400-row export through it before pasting into Excel at all, so the sheet you start working in is already deduplicated and every formula you build afterward reflects accurate totals.