Find what is missing from either list

A lookup formula answers one direction at a time. Load both lists, pick the column they share, and see what is missing from each side at once.

What this catches

  • Records in the first list with no match in the second
  • Records in the second list with no match in the first
  • Records present in both, but with values that differ
  • The same key appearing more than once on either side

You will be asked which column identifies a row. Whichever column both lists share — an ID, code or reference number.

File A · original

Drop a CSV or XLSX file here, or click to browse

File B · updated

Drop a CSV or XLSX file here, or click to browse

All file data is read entirely within this browser tab. Nothing is uploaded to any server. Closing this tab discards all loaded data.

How it works

  1. Load one list into each side. They do not need the same columns or the same row order.
  2. Pick the column the two lists have in common.
  3. Read the removed count for what is missing from the second list, and the added count for what is missing from the first.
  4. Export the result if you need to send it on.

Questions

How do I find records missing from one of two lists?
Load a list into each side and pick the column they share. Records with no match on the other side are counted as added or removed depending on which list they are missing from, so both directions are answered at once.
Is this easier than using a lookup formula?
A lookup checks one direction, so finding what is missing from both sides means running it twice and reconciling the results by hand. Here both directions come out of a single comparison, along with the records that exist on both sides but differ.
Do the two lists need the same columns?
No. They only need one column in common to match records on. Columns that exist on only one side are reported so you know they were not compared.
Is my file uploaded anywhere?
No. Both files are read and compared inside this browser tab. Nothing is sent to a server, there is no account, and closing the tab discards everything.
What file formats does it accept?
CSV and XLSX. Both sides can be different formats — a CSV against an XLSX works.
How large a file can it handle?
It has been measured on 100,000 rows a side. Large files take a few seconds to parse, and the comparison itself runs in well under a second.
Can I export the differences?
Yes. The result can be exported as CSV or XLSX, so you can attach it or keep it with the period’s paperwork.