Open both Excel sheets in separate windows
Arrange the windows side by side
Use View > View Side by Side
Use View > Synchronous Scrolling if needed
Compare sheet names, headers, and column order
Check row counts in both sheets
Compare key values cell by cell
Use formulas like =A1=Sheet2!A1 to test matches
Use Conditional Formatting to highlight differences
Use Go To Special to find blanks, formulas, or constants
Sort both sheets by the same key before comparing
Use Excel’s Compare Files feature if available
Use Power Query to merge and compare data
Use VLOOKUP, XLOOKUP, or MATCH to find missing records
Use IF formulas to flag mismatched cells
Use a third-party comparison tool for large files