The square root button is usually marked with a √ symbol, and on most calculators you enter the number first, then press it

On a basic calculator, the square root function finds the number that, when multiplied by itself, equals your starting number. For example, the square root of 9 is 3, because 3 × 3 = 9. The button is almost always labeled with the √ symbol, though its exact location and how you use it varies slightly depending on your calculator type.

The most common approach is to type your number, then press the √ button. Some scientific calculators work the opposite way — you press √ first, then type the number. A few older or specialty calculators require you to press a shift or function key to access the square root feature. If you are not sure which method your calculator uses, try the number-first approach, since that is the standard on most phones and basic handheld calculators.

Key Takeaways

  • On most calculators, you type the number, then press the √ button to get the square root.
  • Scientific calculators sometimes reverse this order — press √ first, then type the number.
  • If the √ button is not visible, look for a shift, function, or second key that unlocks hidden operations.
  • Phone calculator apps usually show the square root button only when you rotate to landscape mode or tap a menu.

Finding the square root button on a basic handheld calculator

On most basic calculators sold in stores, the √ symbol is printed directly on a button, usually in the upper rows. Enter your number using the number pad, then press √. The result appears on the display immediately. If you do not see a √ button at all, your calculator may not have a square root function — very simple four-function calculators (addition, subtraction, multiplication, division only) often skip it.

Some calculators place the √ button on the right side of the display area, while others put it near the top. Look for the symbol itself rather than a word label. If you find a button labeled "2nd" or "Shift" in a different color, press that first, then look for √ printed above or below another button in smaller text — that is where the square root function is hidden on calculators with limited button space.

Using square root on a scientific calculator

Scientific calculators have more functions and often arrange them differently. Many scientific models ask you to press √ before entering your number. Type the number, press equals, and the square root appears. However, some scientific calculators follow the standard number-first method, so check your manual or try both ways on a test number you know — the square root of 4 is 2, so that is a safe test.

Scientific calculators often have a √ button on the left side of the keypad, sometimes grouped with other math functions like sine, cosine, and logarithm. If you cannot find it, look for a button labeled "Shift" or a colored key that unlocks a second layer of functions. Press that key, then scan the buttons again — you may see √ printed in smaller text above or beside another button.

Finding square root on your phone calculator

The calculator app on your phone usually hides the square root button to keep the display simple. On iPhone, open the Calculator app and rotate your phone to landscape mode — the scientific functions, including √, appear on the left side. On Android, open your calculator app and look for a menu icon (three horizontal lines or three dots), then tap it to reveal more functions. Some Android calculators show a "Sci" or "Scientific" button that switches to an expanded view.

Once you see the √ button, the process is the same: type your number, then tap √. The result shows on your screen. If your phone's default calculator does not have this feature, you can download a scientific calculator app from your phone's app store — search for "scientific calculator" and choose one with good reviews.

What to do if your result looks wrong

Square roots of whole numbers often produce decimals. For example, the square root of 2 is approximately 1.414, not a clean whole number. This is normal and correct. If your calculator shows a very long decimal, it is displaying the full precision — you can round it to fewer decimal places if you need to use it elsewhere.

If your calculator shows an error message or "E" on the display, you may have tried to find the square root of a negative number. Most basic calculators cannot do this, because there is no real number that, when multiplied by itself, produces a negative result. Scientific calculators can handle negative square roots using imaginary numbers, but that is beyond what most everyday tasks require. Simply try a positive number instead.

Keyboard shortcuts on computer calculators

If you are using the calculator app on Windows or Mac, you can often type the square root without clicking the button. On Windows Calculator in scientific mode, press "R" on your keyboard to trigger the square root function. On Mac Calculator, the keyboard shortcut varies depending on which version you have, so check the Help menu or try clicking the √ button once to see if a keyboard shortcut appears.

For web-based calculators or spreadsheet programs like Excel or Google Sheets, you typically type a formula instead of clicking a button. In Excel or Google Sheets, type =SQRT(number) in a cell, replacing "number" with your actual number or a cell reference. Press Enter, and the square root appears in that cell.

Frequently Asked Questions

Can I find the square root of a negative number?

Basic calculators cannot find the square root of a negative number and will show an error. Scientific calculators can, but they use imaginary numbers, which is a more advanced math concept. For everyday use, stick to positive numbers.

What is the square root of zero?

The square root of zero is zero. This is correct and not an error — zero times zero equals zero, so the square root of zero is zero.

Why does my calculator show so many decimal places?

Your calculator is showing the full precision of the result. Most square roots of non-perfect numbers produce endless decimals. You can round the result to however many decimal places you need — two or three decimal places is usually enough for everyday purposes.

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

No. Four-function calculators handle only addition, subtraction, multiplication, and division. If you need square root, you need a basic scientific calculator, which costs only a few dollars and is widely available.

What if I need to find the square root of a really large number?

Any calculator, phone, or computer can handle large numbers. Type or enter the number normally, then press or use the square root function. The result may be a very large decimal, but the process is the same.