Compare Two Lists: Find Matches and Missing Values

Complete the task

1. Paste one value per line into List A and List B. Do not include a column header unless it is itself a value to compare.
2. Review Trim edges and Ignore letter case before comparing. The defaults trim edges and keep letter case significant. Repeated values count once under the chosen rule.
3. Compare lists, inspect the Only A, In both and Only B totals, then choose a result filter. Copy or download exports only the selected result category; All exports the full comparison.

Worked example

The built-in invoice lists return 2 only in A (INV-1001 and INV-1003), 2 in both (INV-1002 and INV-1004), and 2 only in B (INV-1005 and INV-1006). The repeated INV-1004 in List A is reported as one collapsed entry. Choose Only A to download the two missing invoice values rather than all six comparison rows.

Method and limits

This is a unique-value comparison, not a row-by-row table join or an occurrence-count reconciliation. Empty lines are skipped; with Trim edges enabled, whitespace-only lines are skipped too. Trimming also changes the displayed output value, and case-insensitive matching retains the first encountered spelling. Use the related Excel guide when repeated IDs represent separate records. Each input is limited to 5 MiB and 20,000 lines. The default CSV export protection prefixes formula-like values, including negative numbers, with an apostrophe; review it when exact strings are required. CSV output cannot enforce Excel cell types.