What OR does
OR combines multiple logical tests into one TRUE or FALSE result. Use it when a formula should pass if any one of the supplied conditions is true.
Practical examples
Flag rows that meet either condition
=OR(B2="Overdue",C2="High")
This returns TRUE when a row is overdue or marked as high priority.
Use OR inside IF
=IF(OR(D2<0,D2>100),"Check value","OK")
This catches values outside an allowed range and labels only those rows for review.
Common mistakes and notes
OR returns TRUE when any condition passes
That includes the first TRUE condition and any later ones. If you need all conditions to pass, use AND instead.
Wrap OR with IF when you need text output
OR by itself does not return labels or actions. Combine it with IF if you want outputs like Alert or OK.
Quote text conditions
Text comparisons such as "Overdue" or "High" need quotation marks. Otherwise Excel interprets them as names rather than literal text values.