To calculate with a formula in Excel, type an equal sign, then the two cells you want to combine with an operator between them. =A1+B1 adds them, =A1-B1 subtracts B1 from A1, =A1*B1 multiplies them (the * is an asterisk, not the letter x), and =A1/B1 divides A1 by B1 (the / is a forward slash). Every formula starts with =; leave it off and Excel keeps your entry as text instead of calculating it.
The same four operators work whether you point at cells or type plain numbers, so =12*5 returns 60 in exactly the way =B2*C2 does. A subtraction reads left to right: in the grid below, =B2-C2 takes the amount spent away from the budget.
| A | B | C | D | |
|---|---|---|---|---|
| 1 | Category | Budget | Spent | Left |
| 2 | Rent | 2,000 | 1,700 | 300 |
The four operators
Each basic operation is one keystroke. Type the first cell, the operator, then the second cell:
+adds:=B2+C2.-subtracts:=B2-C2takes C2 away from B2.*multiplies:=B2*C2. The multiply sign is the asterisk, not the letter x./divides:=B2/C2divides B2 by C2. The divide sign is the forward slash, not the backslash.
Order matters for - and /, because =B2-C2 and =C2-B2 come out with opposite signs and =B2/C2 is not the same as =C2/B2. It does not matter for + and *, where swapping the two cells gives the same answer.
There is no SUBTRACT function
Most operations pair with a function, but subtraction does not. Microsoft’s own subtraction guide says so outright: “There is no SUBTRACT function in Excel.” You subtract with the - operator, the way you would on paper. Addition is the one operation that has both forms, so =B2+C2 and =SUM(B2:C2) return the same total, and the guide to what a formula is and how SUM works covers the function version.
Multiplication has the same pair of forms in reverse: the * operator for two cells, and grids often use it to extend a rate across a row.
| A | B | C | D | |
|---|---|---|---|---|
| 1 | Item | Units | Price | Total |
| 2 | Cable | 12 | 5 | 60 |
Which operator runs first
When a formula mixes operators, Excel does not simply read left to right. Multiplication and division run before addition and subtraction, so =10-2*3 works out to 4, not 24, because 2*3 is calculated first. Parentheses force the order you mean: =(10-2)*3 returns 24. That is the whole rule you need for arithmetic; the full operator order, including exponents and comparisons, is laid out in the formula symbols reference.
Add up a whole column fast
To total a column you do not have to type every cell: AutoSum writes the whole =SUM(...) for you from one click on the Home tab. It is quick because it guesses the range, and it can guess wrong when a blank row or a header sits inside the column, which is what that page covers. For an average or a count of the same column, reach for the functions in Excel’s counting functions instead of a sum.
When the answer is not a number
An arithmetic formula calculates cleanly when the cells hold real numbers. If a cell holds a word or a stray character instead, an operator like - has nothing numeric to work with and the formula returns #VALUE!. A function behaves differently: Microsoft notes that “Functions often ignore text values and calculate everything as numbers, eliminating the #VALUE! error,” so a =SUM(...) over the column keeps calculating where a =B2-C2 on the same non-numeric cell errors.
| A | B | C | D | |
|---|---|---|---|---|
| 1 | Invoice | Billed | Paid | Balance |
| 2 | 1004 | 2,000 | pending | #VALUE! |
A related trap is a number that is only stored as text. A SUM built over the column skips it, so the total can read low with no cell showing an error, and numbers stored as text covers how to spot and convert them.
The short version
- Type
=, then the two cells with an operator between them:+adds,-subtracts,*multiplies,/divides. - The
*is an asterisk (not the letter x) and the/is a forward slash (not a backslash). Order matters for-and/, not for+and*. - There is no SUBTRACT function: subtraction is the
-operator. Addition can use+orSUM. - Multiplication and division run before addition and subtraction; parentheses override the order. The full order is in formula symbols, and what a formula is covers the parts of one.
- To total a column in one click instead of typing each cell, use AutoSum.
Fixing arithmetic usually means editing a formula and saving over the earlier file. To check that the edit changed what you meant and nothing else moved, compare the two saved workbooks: each cell you changed shows its before and after value, and on the formula itself the exact piece that moved is boxed, so a fixed operator or a repointed cell is spelled out instead of hunted for.
