SUMIF and SUMIFS Formula Generator

The trap that catches everyone

• SUMIF and SUMIFS order their arguments differently. SUMIF is (criteria range, criterion, sum range) — the range to add is last. SUMIFS is (sum range, criteria range, criterion, ...) — the range to add is first. Adding a second condition to a working SUMIF therefore means rewriting it, not just appending.
• Swapping them returns a number, not an error. Both arguments are ranges, so Excel accepts the wrong order and adds up the wrong column. Nothing warns you.
• Comparing against a cell needs the ampersand. ">"&B1, the same rule as for COUNTIF, and the same silent zero when you get it wrong.
• The sum range must match the criteria range. Same height, same shape. A mismatch is one of the few mistakes here that produces a visible error.
• Blank conditions are dropped. Fill one condition and the builder writes SUMIF; fill two and it switches to SUMIFS and reorders the arguments for you.

Summing without a condition

That is just SUM(range). SUMIF earns its place only when part of the column should be left out — otherwise it is a longer way to write the same thing.