What IF does
IF is Excel's core decision-making function. It evaluates a condition and then branches to one result when the condition is true and another when it is false.
That makes it useful for pass/fail labels, clean output, error prevention, and business rules that depend on thresholds.
Practical examples
Return a label based on a threshold
=IF(B2>=70,"Pass","Review")
This is the simplest IF pattern: compare a value, then return one of two labels.
Avoid division by zero
=IF(C2=0,"",B2/C2)
Here IF prevents an avoidable error and keeps the report readable when there is no valid denominator.
Common mistakes and notes
Forgetting text quotes
Text results such as "Pass" or "Late" need quotation marks. Numeric results do not.
Over-nesting
Long chains of nested IF formulas become hard to read and hard to debug. When a worksheet depends on many branches, consider lookup tables or functions such as SUMIFS, VLOOKUP, or INDEX plus MATCH.
Leaving the false branch undefined
If you omit value_if_false, Excel returns FALSE. Sometimes that is useful, but on reports it often looks like a mistake.