A function is a built-in formula with a name. These five are the workhorses you'll use every single day.
Summary statistics calculated below a column of figures
| Function | Returns | Example |
|---|---|---|
SUM | Total | =SUM(B2:B13) |
AVERAGE | Mean | =AVERAGE(B2:B13) |
COUNT | How many numbers | =COUNT(B2:B13) |
COUNTA | How many non-empty | =COUNTA(A2:A13) |
MIN | Smallest | =MIN(B2:B13) |
MAX | Largest | =MAX(B2:B13) |
| Month | Sales |
| Jan | 1200 |
| Feb | 1500 |
| Mar | 900 |
| ----- | ----- |
| Total | =SUM(B2:B4) → 3600
| Avg | =AVERAGE(B2:B4) → 1200
| Best | =MAX(B2:B4) → 1500
| Worst | =MIN(B2:B4) → 900
| Months| =COUNT(B2:B4) → 3
Select the cell below a column of numbers and press Alt+=. Excel inserts =SUM(...) with the range already guessed. Press Enter to confirm.
[[Alt+=]] (AutoSum) is the single most-used shortcut in Excel. It also works across a row, and across multiple columns at once if you select them first.
COUNT → counts cells containing NUMBERS only
COUNTA → counts cells that are NOT empty (text + numbers)
To count a list of names use COUNTA; COUNT would return 0 because names aren't numbers.
SUM and AVERAGE quietly skip blanks and text in the range — so a stray label won't throw a #VALUE! error. But a blank cell is not the same as zero when averaging: a blank is excluded, a real 0 is included and drags the average down.