Data Cleaning

Real-world spreadsheets rarely arrive clean. Data cleaning in Excel means finding and fixing errors, inconsistencies, and formatting problems before any analysis begins.

Removing Duplicates

Data tab -> Remove Duplicates -> select the relevant columns

Trimming Extra Spaces

Leading, trailing, or repeated spaces are a common source of failed lookups and mismatches.

=TRIM(A2)

Fixing Text Case

=UPPER(A2)   ' ALL CAPS
=LOWER(A2)   ' all lowercase
=PROPER(A2)  ' Title Case

Handling Blank Cells and Errors

Go To Special (Ctrl + G then Special) can select all blank cells at once so they can be filled or deleted in bulk. IFERROR is useful for replacing formula errors with a clean placeholder value.

=IFERROR(A2/B2, "N/A")

Text to Columns

Splits a single column of combined data (like "City, State") into separate columns based on a delimiter.

Data tab -> Text to Columns -> Delimited -> choose delimiter (e.g. comma)