NESTED IFS
What it's for
A single IF formula checks one condition and gives one of two answers. A "nested" IF is what happens when you put another IF formula inside the first one, letting you check several conditions in a row and land on different answers depending on which one turns out true.
When you'd use it
Anywhere you're sorting something into more than two categories based on a number or condition — assigning letter grades based on a score, labeling orders as "small," "medium," or "large" based on quantity, or flagging performance tiers based on a target.
How it works
Excel checks conditions in the exact order you write them, top to bottom, and stops at the very first one that's true. Everything after that point in the formula is never even looked at for that row. This matters more than it might seem — nested IFs need to be ordered from most specific to least specific, or a later, more precise condition might never get a chance to run.
A worked example
=IF(A2>90, "A", IF(A2>80, "B", "C"))Excel first asks: is A2 greater than 90? If yes, the answer is "A" and it stops there. If no, it checks: is A2 greater than 80? If yes, "B." If neither is true, the formula falls through to "C."
A tip worth knowing
The order matters more than the conditions themselves. If this same formula were written checking A2>80 before A2>90, a score of 95 would incorrectly return "B" — because 95 is also greater than 80, and Excel would have already stopped there without ever checking the more specific 90 threshold.
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