Step 1: choose the common key
Pick the column that exists in both spreadsheets. Good keys include employee code, email address, asset serial number, asset tag, invoice number or vendor reference. Avoid names if a better key exists.
Step 2: keep lookup key in the first column
Classic VLOOKUP searches the first column of the selected table. If your lookup key is not first, rearrange a copy of the data or use XLOOKUP/INDEX MATCH instead.
Step 3: write the formula
In the source sheet, reference the lookup value, target table range, return column number and exact-match setting. Wrap the formula with IFERROR to show a friendly missing message.
Step 4: review missing and duplicates
A not-found result means the key was not found, but it does not automatically tell you about duplicates or conflicts. Check duplicate keys before final management reporting.
ReconNimble method
Upload both spreadsheets, select the matching key, run reconciliation and export missing records, duplicates, matched rows and an action sheet. The workflow is safer for full-file comparison than copying formulas row by row.