Square root in Excel and Google Sheets

You need the square root of 144 for a budget sheet, and the answer is 12. But every spreadsheet user hits the moment when square root in excel is not just a math problem, it is a syntax problem. The SQRT tool exists, the caret works, and negative numbers break everything unless you know the rule. Here is exactly what to type.

Microsoft Support defines the SQRT function as SQRT(number). The argument must be a non-negative real number. If you enter =SQRT(144), the result is 12. For a cell reference, =SQRT(B4) gives the square root of whatever is in B4.

The Principal Root Is All You Get

The principal square root, the non-negative one, is always what SQRT produces. A positive number has two square roots, but the function delivers only the positive one. If you need the negative root, multiply the result by -1: =-SQRT(144) gives -12.

SQRT cannot handle a negative radicand. Enter =SQRT(-4) and Excel shows #NUM!, the error for an invalid numerical input.

Every spreadsheet also computes a square root through exponentiation. Raising a number to the power of 0.5 is identical to taking its square root. Type =144^0.5 and you get 12. The POWER function, documented by Microsoft Support as POWER(number, 1/2), does the same thing: =POWER(144, 0.5) equals 12.

Nth Roots Beyond Square

The caret method extends to any root. For a cube root, use exponent 1/3: =27^(1/3) returns 3. For a fourth root, =16^(1/4) returns 2. Neither SQRT nor POWER can handle a root other than square without the fractional exponent form, but the caret works for all of them.

The sqrt #num error appears the moment you feed a negative number into SQRT. =SQRT(-9) shows #NUM! because the principal square root of a negative number is not a real number. The error is not a bug, it is the spreadsheet enforcing real-number math.

Work Around the Imaginary Result

If you actually need the square root of a negative number, for example, working with the imaginary unit i where i = √(-1), you must work around it. In real-number spreadsheets, no built-in tool returns an imaginary result. Use an IF statement to detect negatives and handle them separately, or avoid the input entirely by squaring the negative value first: =SQRT(-9^2) gives 9, because the exponent is evaluated before the square root.

Typing the square root symbol in excel is not about calculation, it is about display. The radical symbol (√) is a character, not a function. To insert it, copy it from the Character Map. Once in a cell, you can prepend it to a number: "√144" appears, but Excel treats that cell as text, not a formula.

If you need the symbol alongside a calculated result, concatenate it: ="√ " & SQRT(144) displays √ 12. The same trick works for Google Sheets.

The google sheets square root tool is identical to Excel's. Google Sheets function list defines SQRT(number) with the same rules: =SQRT(81) gives 9. The caret operator also works: =81^0.5 gives 9. The POWER tool is available as =POWER(81, 0.5).

Negative numbers in SQRT produce #NUM! in Google Sheets just as they do in Excel. There is no separate tool for imaginary results. The symbol insertion differs slightly, use Insert > Special characters and search for "square root" or paste it directly.

The table below shows the SQRT output for radicands you are likely to encounter in school or work. Each value is the principal square root.

The SQRT tool suits anyone who needs a fast, accurate decimal answer for a real, non-negative radicand. That includes spreadsheet users, DIY project calculators, parents helping with homework, and students verifying a manual approximation. It also suits middle-school and high-school students learning perfect squares and the radical symbol for the first time, because the tool returns the principal square root exactly as the math curriculum defines it.

When To Use Something Else

Anyone needing cube roots, nth roots beyond square roots, or advanced complex analysis beyond i = √(-1) should skip the SQRT tool entirely. For cube roots, use the caret operator with 1/3. For anything involving imaginary numbers, no spreadsheet tool gives a direct answer. You need a calculator or software that supports complex numbers.

The single thing that goes wrong most often: entering a negative radicand and assuming the error means the answer does not exist. The answer exists, it just is not a real number, and a real-number function cannot return it.