jakup

The “reference” we check membership against.

Finds items here that are not in the reference.

When comparing two columns helps

Sometimes you are handed two lists and need to know who dropped off and who is new. If the sort order differs or there are many rows, checking by eye is exactly where mistakes creep in.

In Excel this is usually done with COUNTIF: if =COUNTIF(B:B, A2) returns 0, the value in A2 is not present in column B. Checking both directions means building the formula twice, which is tedious. Here you paste both lists once and see the result from both sides together.

Cleaning up spaces and letter case before comparing matters. Two values can look identical while one carries a trailing space, and they will be treated as different. Pasted data is processed only in your browser and never sent to a server.