Start with the equals sign, then type what you want to calculate

Every calculation in Excel begins with an equals sign. When you type = into a cell, Excel knows you are about to write a formula instead of just text. After the equals sign, you type the math you want done — either using cell references (like A1 or B3) or actual numbers, or both together.

The simplest formula is just addition. If you type =5+3 into a cell and press Enter, Excel shows you 8. If you type =A1+A2, Excel adds whatever numbers are sitting in cells A1 and A2, and shows you the result. The power of this is that if you change the number in A1, the result updates automatically — you do not have to recalculate by hand.

Key Takeaways

  • Every formula starts with an equals sign, followed by the math you want done using cell names like A1 or actual numbers.
  • The four basic operations are addition (+), subtraction (−), multiplication (*), and division (/), and you can combine them in one formula.
  • When you copy a formula down a column, Excel automatically adjusts the cell references so each row calculates its own data.
  • Built-in functions like SUM, AVERAGE, and COUNT let you work with many cells at once without typing each one individually.
  • Parentheses control the order of operations — Excel always does what is inside parentheses first, just like in math class.

The four basic operations and how to combine them

Excel handles the four operations you learned in school: addition (+), subtraction (−), multiplication (*), and division (/). You can use any of these in a single formula. For example, =A1+B1*2 takes the number in B1, multiplies it by 2, then adds the number in A1. Excel follows the standard order of operations — multiplication and division happen before addition and subtraction.

If you want to change that order, use parentheses. The formula =(A1+B1)*2 adds A1 and B1 first, then multiplies the result by 2. That gives a different answer than the previous example. Parentheses always go first, no matter what operation is inside them.

A practical example: if column A holds hourly wages and column B holds hours worked, the formula =A1*B1 calculates total pay for that row. If you want to add a 10 percent bonus, use =A1*B1*1.1 or =(A1*B1)*0.1+A1*B1 — both give the same result.

Copying formulas down a column so each row calculates itself

Once you write a formula in one cell, you can copy it down to other rows and Excel adjusts the cell references automatically. If you write =A1+B1 in cell C1, then copy that formula down to C2, Excel changes it to =A2+B2. In C3 it becomes =A3+B3, and so on. This is called a relative reference — the cell names shift relative to where you copy the formula.

To copy a formula down, click the cell that holds the formula, then drag the small square in the bottom-right corner of that cell down as far as you need. Alternatively, click the cell, copy it (Ctrl+C on Windows or Command+C on Mac), then select the range where you want it and paste (Ctrl+V or Command+V). Excel fills in the adjusted references for you.

Sometimes you want a cell reference to stay the same when you copy. Use a dollar sign before the letter and number — =$A$1 will not change no matter where you copy the formula. This is called an absolute reference. You can also lock just the column or just the row: =$A1 keeps the column fixed but lets the row change, and =A$1 keeps the row fixed but lets the column change.

Using built-in functions to work with many cells at once

Functions are pre-written formulas that do common tasks. Instead of typing =A1+A2+A3+A4+A5, you can type =SUM(A1:A5) and get the same result. The colon between A1 and A5 means "all cells from A1 through A5." This saves time and reduces mistakes when you are adding up dozens of cells.

Other common functions include AVERAGE (which adds up cells and divides by how many there are), COUNT (which counts how many cells hold numbers), MIN (which finds the smallest number), and MAX (which finds the largest). You use them the same way: =AVERAGE(B2:B10) finds the average of cells B2 through B10, and =MAX(C1:C100) finds the highest number in that range.

You can also nest functions inside each other. For example, =ROUND(AVERAGE(A1:A10),2) calculates the average of A1 through A10, then rounds it to 2 decimal places. Excel works from the inside out — it calculates AVERAGE first, then feeds that result to ROUND.

Understanding operator order and when parentheses matter

Excel follows the same order of operations as math: multiplication and division before addition and subtraction, left to right. The formula =2+3*4 gives 14, not 20, because Excel multiplies 3 by 4 first (getting 12), then adds 2. If you want to add 2 and 3 first, you must write =(2+3)*4, which gives 20.

This matters most when you are mixing operations. The formula =A1/B1+C1 divides A1 by B1, then adds C1 to that result. But =A1/(B1+C1) adds B1 and C1 first, then divides A1 by that sum. These give very different answers. When in doubt, use parentheses — they make your intention clear and prevent mistakes.

Checking your work and fixing common formula errors

If a cell shows an error code instead of a number, something went wrong. #DIV/0! means you tried to divide by zero or by an empty cell. #REF! means the formula refers to a cell that no longer exists — often because you deleted a column or row. #VALUE! means the formula is trying to do math on text instead of numbers. #NAME? means Excel does not recognize a function name, usually because of a typo.

To find the problem, click the cell with the error and look at the formula bar at the top — it shows exactly what the formula says. Check that all cell references point to the right place, that function names are spelled correctly, and that you have not accidentally included text where numbers should be. If a cell is supposed to hold a number but shows text, Excel will not use it in calculations.

You can also use the Trace Error tool: in Excel, go to the Formulas tab and click Error Checking. It walks through errors one at a time and suggests fixes. For a quick check, click a cell with a formula and look at the cells it references — Excel highlights them in color so you can see which data is being used.

Real examples: payroll, budgets, and inventory

A payroll sheet might have employee names in column A, hourly rate in column B, and hours worked in column C. Column D calculates pay with =B2*C2 (rate times hours). If there is overtime, you might use =IF(C2>40,(40*B2)+(C2-40)*B2*1.5,B2*C2) — this checks if hours exceed 40, and if so, pays regular time for the first 40 hours and time-and-a-half for the rest. Copy this formula down for each employee.

A budget spreadsheet might list categories in column A, budgeted amounts in column B, and actual spending in column C. Column D calculates the difference with =B2-C2 (positive means you spent less than planned). At the bottom, =SUM(B:B) totals the entire budget column, and =SUM(C:C) totals actual spending. A final cell shows =B10-C10 (or whatever row holds your totals) to show overall surplus or shortfall.

An inventory sheet might track item names, quantity on hand, and reorder level. A formula like =IF(B2 checks whether quantity on hand (B2) is below the reorder level (C2), and displays "Order" or "OK" accordingly. This flags items that need restocking without you having to scan the whole sheet manually.

Frequently Asked Questions

Why does my formula show the formula itself instead of the answer?

The cell is probably formatted as text. Right-click the cell, choose Format Cells, and change the format to Number or General. Then edit the formula (press F2 or double-click the cell) and press Enter. Excel will now calculate it instead of displaying it as text.

Can I use a formula to pull data from a different sheet?

Yes. Type the sheet name, then an exclamation point, then the cell reference: =Sheet2!A1+Sheet2!B1 adds cells from Sheet2. If the sheet name has spaces, put it in single quotes: ='Sales Data'!A1. You can also reference other workbooks, though the syntax is more complex.

What is the difference between a formula and a function?

A formula is any calculation you write starting with an equals sign — =A1+B1 is a formula. A function is a pre-built formula that does a specific task — SUM, AVERAGE, and COUNT are functions. All functions are formulas, but not all formulas are functions.

How do I make a formula that rounds to the nearest dollar?

Use the ROUND function with 0 decimal places: =ROUND(A1,0) rounds A1 to the nearest whole number. If you want to always round down, use FLOOR: =FLOOR(A1,1). If you want to always round up, use CEILING: =CEILING(A1,1).

Can I write a formula that does different things based on a condition?

Yes, using the IF function. =IF(A1>100,"High","Low") checks if A1 is greater than 100 and displays "High" if true, "Low" if false. You can nest multiple IFs: =IF(A1>100,"High",IF(A1>50,"Medium","Low")) creates three categories. For many conditions, consider using VLOOKUP or INDEX/MATCH instead.