Square Root Calculator

Calculate square roots, cube roots, and any nth root with exact and decimal results.

Root Calculator

144 =

12

Verification: 12^2144

Square Root Calculator Formula & How It Works

√n = n^(1/2) | ∛n = n^(1/3) | ⁿ√x = x^(1/n)
  • Square root: the number that when squared gives n
  • √9 = 3 because 3² = 9
  • Negative numbers have no real square root (imaginary: √-1 = i)
  • nth root: x^(1/n), or equivalently x^0.5 for square root

The square root of a number n is the value that when multiplied by itself gives n. Perfect squares (1, 4, 9, 16, 25…) have whole-number square roots. Others are irrational: √2 = 1.41421… For cube roots and higher, the same logic applies with the appropriate exponent.

Square Root Calculator FAQs

How do you calculate a square root by hand?

For non-perfect squares, use the Babylonian method: guess a value g, then refine with g = (g + n/g) / 2, repeat until stable. For √2: start with g=1 → g=(1+2)/2=1.5 → g=(1.5+1.333)/2=1.4167 → converges to 1.41421.

What is the square root of a negative number?

In real numbers, negative numbers have no square root (no real number squared gives a negative). In complex numbers, √(−1) = i (imaginary unit). √(−9) = 3i.

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