Formulas are the reason Excel exists: they let the programme do the arithmetic for you, and update automatically when your figures change. By the end of this page you will be able to write your first formula and understand why it is better than typing the answer yourself.
To tell Excel you are writing a formula rather than plain text, you always start by typing an equals sign, =. That single character is a signal: everything that follows will be treated as something to calculate, not just words to display. For example, typing =2+2 into a cell and pressing Enter shows the answer, 4, in that cell.
- The formula itself, starting with =
- The answer, 15, appears here
Suppose cell A1 holds 10 and A2 holds 5. Rather than typing =10+5, you would type =A1+A2. The answer, 15, appears in your formula's cell, but if you later change A1 to 20, the formula quietly recalculates to 25 without you touching it again. This is the single biggest reason to use formulas: they stay correct even after your figures change. The four basic symbols are + for add, - for subtract, * for multiply, and / for divide.
Try it yourself
In cell A1 type 10, and in A2 type 5, then press Enter after each.
This gives the formula something real to point at, rather than working with typed-in numbers.
Click A3 and type =A1+A2, then press Enter.
This adds the contents of the two cells together and shows the result, 15, in A3.
Change the value in A1 to 20 and watch A3.
This shows the formula updating automatically, which is the whole point of using cell references.
In A4, type =A1*A2 and press Enter, then in A5 type =A1/A2.
This practises multiply and divide, the asterisk and forward slash, alongside add and subtract.
In A6, type =(A1+A2)*2 and compare it to =A1+A2*2 in A7.
This shows how brackets change the order Excel calculates in, giving two different answers from the same numbers.
Words people use
Once writing a simple formula feels comfortable, you have unlocked the main reason people use spreadsheets at all. Later lessons build on exactly this idea, just with more powerful instructions than plus and minus.
Check yourself
If you can say yes to each of these, you are ready for the next lesson.
- I know every formula starts with an equals sign.
- I can write a formula that refers to other cells instead of typing numbers.
- I can use +, -, * and / in a formula.
- I understand why brackets can change the answer.