The quickest way to square root on most calculators

On a standard calculator, press the number you want to find the square root of, then press the square root button. The square root button looks like a checkmark or radical symbol (√) and is usually near the top or side of the keypad. Your calculator will show the answer immediately.

If your calculator doesn't have a dedicated square root button, you can use the exponent function instead. Press your number, then the exponent button (usually marked ^ or x^y), then type 0.5, and press equals. This works because a square root is the same as raising a number to the power of 0.5.

The method changes slightly depending on whether you're using a basic calculator, a scientific calculator, or a calculator app on your phone. The sections below walk through each type.

Key Takeaways

  • Most calculators have a dedicated square root button (√) that gives you the answer in one press after entering your number.
  • If your calculator lacks a square root button, you can use the exponent function by entering your number, pressing the exponent button, typing 0.5, and pressing equals.
  • Scientific calculators often require you to press the square root button before entering the number, while basic calculators require you to enter the number first.
  • Phone calculator apps work the same way as physical calculators, though you may need to rotate your phone to landscape mode to see the square root button.

Square root on a basic calculator

A basic calculator is the kind you find in most homes and offices — it has four operations (add, subtract, multiply, divide) and maybe a few extra buttons. To find a square root on a basic calculator, enter the number first, then look for the √ button. Press it, and the answer appears on the screen.

For example, to find the square root of 16, you would press 1, then 6, then √. The screen shows 4. If you don't see a √ button on your calculator, check whether it has a second function layer. Some basic calculators hide the square root function under a "2nd" or "Shift" button. Press that button first, then look for √ printed above another button. Press the button below it, and the square root function activates.

If your basic calculator still has no square root option, the exponent method works on almost all calculators. Enter your number, press the button marked ^ or x^y, type 0.5, and press the equals button. The result is your square root.

Square root on a scientific calculator

Scientific calculators have many more buttons and functions than basic calculators. They're designed for math, physics, and engineering work. On most scientific calculators, the square root button is visible on the face, often marked √ or sqrt. However, the order of operations is different from a basic calculator.

On a scientific calculator, press the √ button first, then enter your number, then press equals. For example, to find the square root of 25, you press √, then 2, then 5, then =. The screen shows 5. This reverse order confuses people switching from a basic calculator, so test it with a number you know (like 16, which equals 4) before using it on a problem that matters.

Some scientific calculators also display a second function layer. If you press "2nd" or "Shift" and then look at the buttons, you may find another square root option or a different way to access the function. Check your calculator's manual or the printed labels above the buttons to see what's available.

Square root on a phone calculator app

The calculator app on your phone works like a basic calculator when held in portrait mode (vertical). Enter your number, then look for the √ button. If you don't see it, rotate your phone to landscape mode (horizontal). Most phone calculator apps expand to show scientific functions when you turn the phone sideways, and the square root button usually appears then.

On an iPhone, the built-in Calculator app shows the √ button only in landscape mode. On Android phones, the default calculator app varies by manufacturer, but most follow the same pattern. Enter your number, rotate to landscape, and tap √. The answer appears instantly.

If your phone's calculator app doesn't have a square root button even in landscape mode, you can download a scientific calculator app from your phone's app store. Search for "scientific calculator" and choose one with good reviews. Most are free and work the same way as the examples above.

Using the exponent method when square root isn't available

If your calculator has no square root button anywhere, the exponent method works on nearly every calculator that has an exponent function. The exponent button is usually marked as ^ or x^y. This method works because mathematically, the square root of a number is the same as raising that number to the power of 0.5.

Here's the step-by-step process: Enter your number. Press the exponent button (^ or x^y). Type 0.5. Press equals. For example, to find the square root of 36, you enter 36, press ^, type 0.5, and press =. The screen shows 6.

This method also works for other roots. To find the cube root (the number that multiplies by itself three times to make your original number), use 0.333 instead of 0.5. To find the fourth root, use 0.25. The pattern is: divide 1 by the root you want, and use that decimal as your exponent.

Common mistakes when finding square roots

The most common mistake is pressing buttons in the wrong order. On a basic calculator, always enter the number first, then press √. On a scientific calculator, press √ first, then enter the number. Test with 16 (which should give 4) to make sure you have the order right before you use it on your actual problem.

Another mistake is forgetting that square roots of negative numbers don't work on a standard calculator. If you try to find the square root of -9, most calculators show an error or "E" on the screen. This is correct — there is no real number that multiplies by itself to make a negative number. If you see an error, check that you entered a positive number.

A third mistake is confusing the square root button with the squared button. The squared button (usually marked x² or x^2) does the opposite — it multiplies a number by itself. If you press the wrong button, you'll get a much larger number than you expected. Look carefully at the label before you press.

Checking your answer

To verify that your square root is correct, multiply the answer by itself. If you found that the square root of 144 is 12, multiply 12 by 12 on your calculator. If you get 144, your square root was correct. If you get a different number, you may have made an error or pressed the wrong button.

This check works for any square root. It's especially useful when you're learning or when you're not sure whether you pressed the buttons in the right order. A quick multiplication takes only a few seconds and catches mistakes before they affect your work.

Frequently Asked Questions

What's the difference between the square root button and the squared button?

The squared button (x²) multiplies a number by itself. The square root button (√) finds the number that, when multiplied by itself, makes your original number. They do opposite things. Squaring 5 gives 25. The square root of 25 gives 5.

Can I find the square root of a decimal number?

Yes. Enter the decimal number the same way you would enter a whole number, then press the square root button. For example, the square root of 2.25 is 1.5. Decimals work exactly like whole numbers on a calculator.

Why does my calculator show a very long decimal for some square roots?

Some numbers don't have a perfect square root. The square root of 2, for example, is approximately 1.41421356... and goes on forever without repeating. Your calculator rounds it to fit the screen. This is normal and correct.

What if my calculator shows a negative square root?

Technically, every positive number has two square roots — one positive and one negative. For example, both 3 and -3 multiply by themselves to make 9. Most calculators show only the positive square root, which is what you need for most everyday problems. If your calculator shows a negative result, you likely pressed a negative sign by accident.

Does the square root method work the same on all phones?

The basic method is the same, but the button locations vary. iPhones show the √ button only in landscape mode. Android phones vary by manufacturer. If you can't find the square root button, rotate your phone or download a scientific calculator app from your app store.