Most calculators have a square root button labeled √ or a menu option to find it

The square root button is usually on the face of the calculator itself, marked with the symbol √. On basic calculators, you'll find it among the other math operation buttons. On scientific calculators, it may be a second function — meaning you press a "Shift" or "2nd" button first, then the button that holds the √ symbol. On graphing calculators like the TI-84, square root is typically in a math menu you access by pressing the "Math" button.

If you can't find a dedicated button, most calculators let you type the operation into the display. You can usually type "sqrt(" followed by your number and a closing parenthesis, then press Enter. This works on scientific calculators, graphing calculators, and the calculator app on phones and computers.

Key Takeaways

  • The √ button is usually on the face of a basic calculator, or accessed through a "Shift" or "2nd" button on a scientific calculator.
  • On graphing calculators and computer calculator apps, square root is often in a Math menu or typed as "sqrt(number)".
  • The order matters: on most calculators, you enter the number first, then press √, rather than the other way around.
  • A square root finds the number that, when multiplied by itself, gives you the number you started with — so √9 = 3 because 3 × 3 = 9.

How to use square root on a basic calculator

On a standard calculator with a √ button visible on the keypad, the process is straightforward. Type the number you want to find the square root of, then press the √ button. The calculator will display the answer when ready. For example, if you type 16 and press √, the display will show 4.

Some basic calculators work differently — they require you to press √ first, then type the number. Check your calculator's manual or try both ways with a number you know, like 9 (which should give you 3). Once you know which order your calculator uses, you'll be consistent from then on.

How to use square root on a scientific calculator

Scientific calculators often hide the square root function under a second layer of buttons. Look for a button labeled "Shift," "2nd," or "Inv" (for inverse). Press that button first — sometimes it will highlight or change color — then press the button that has √ printed on it. After that, type your number and press Enter or Equals.

The exact sequence depends on your model. On many Casio scientific calculators, you press Shift, then the button marked √. On some HP calculators, you type the number first, then press Shift and √. Again, testing with 9 (which should give 3) will show you the right order for your specific calculator.

How to use square root on a graphing calculator

Graphing calculators like the TI-83, TI-84, and TI-89 store square root in the Math menu rather than on a dedicated button. Press the "Math" button, which opens a menu of functions. Look for an option labeled "sqrt(" or straightforward "√". Select it, and the calculator will place "sqrt(" on your screen. Type the number you want the square root of, add a closing parenthesis, and press Enter.

For example, on a TI-84, you would press Math, scroll to find sqrt, press Enter to select it, type 25), and press Enter again to get 5. Some graphing calculators also let you type sqrt directly without using the menu — try typing "sqrt(25)" and pressing Enter to see if your model supports this shortcut.

How to use square root on your phone or computer

The calculator app on iPhones, Android phones, Windows computers, and Macs all have a square root function, though it's not always visible by default. On an iPhone, open the Calculator app and rotate your phone to landscape mode — the scientific calculator view will appear, and you'll see the √ button. Type your number, then tap √.

On Android, open the calculator app, tap the menu icon (usually three horizontal lines), and select "Scientific" to reveal the √ button. On Windows, open the Calculator app, click the menu icon, and choose "Scientific" mode. On a Mac, open Calculator, go to View, and select "Scientific." In all cases, type your number and click or tap the √ button to get your answer.

What square root actually does

A square root answers the question: what number, when multiplied by itself, gives me this number? The symbol √ is shorthand for "the square root of." So √9 means "what number times itself equals 9?" The answer is 3, because 3 × 3 = 9.

Square roots are useful in real situations. If you know the area of a square room is 144 square feet and you want to find the length of one wall, you'd calculate √144, which equals 12 feet. If you're working with the Pythagorean theorem in geometry, you'll use square root to find the length of a triangle's side. In finance, square root appears in formulas for calculating standard deviation or volatility.

Common mistakes when using the square root button

The most frequent error is pressing buttons in the wrong order. If your calculator expects you to press √ before typing the number, but you type the number first, you'll get an error or a wrong answer. Test your calculator with 4 (which should give 2) to figure out the correct sequence before you rely on it for important calculations.

Another mistake is forgetting to close parentheses when typing "sqrt()" into a calculator app or graphing calculator. If you type "sqrt(25" without the closing parenthesis, the calculator won't process it. Always type "sqrt(25)" with both parentheses, then press Enter. Finally, remember that square roots of negative numbers don't work on basic calculators — they'll show an error. Scientific and graphing calculators can handle them, but they'll display the answer using imaginary numbers, which is a more advanced topic.

Frequently Asked Questions

What's the difference between square root and squaring a number?

Squaring means multiplying a number by itself — so 5 squared (written 5²) equals 25. Square root does the opposite: √25 equals 5. If you square a number and then take its square root, you get back where you started. On a calculator, the square function is usually marked x² and the square root is √.

Can I find the square root of a decimal or a negative number?

Yes for decimals — √2.25 equals 1.5. For negative numbers, basic calculators will show an error because there's no real number that, when multiplied by itself, gives a negative result. Scientific and graphing calculators can calculate square roots of negative numbers, but the answer involves imaginary numbers, which is beyond basic calculator use.

Why does my calculator show a long decimal instead of a whole number?

Some numbers don't have whole number square roots. √2 equals approximately 1.414213562, which goes on forever. Your calculator is rounding to fit the display. This is normal and correct — the calculator is showing you as many decimal places as its screen allows.

Is there a square root button on a basic four-function calculator?

Most basic four-function calculators (addition, subtraction, multiplication, division only) do not have a square root button. You need at least a scientific calculator to access the √ function. If your calculator only has +, −, ×, and ÷ buttons, you'll need to use a different calculator or a calculator app on your phone.