Square Root Calculator
Calculate the square root of any positive number
About this calculator
The square root of a number n is the value that, when multiplied by itself, gives n. Written as √n, it is the inverse of squaring. For example, √144 = 12 because 12 × 12 = 144. Square roots appear in geometry (Pythagorean theorem), physics, statistics (standard deviation), and finance (volatility calculations).
How to use
Enter any positive number. For √2, enter 2 — the result is approximately 1.4142. This is an irrational number, meaning it cannot be expressed as a simple fraction.
Frequently asked questions
What is the square root of a negative number?
In real numbers, negative numbers have no square root. In complex mathematics, the square root of −1 is defined as i (the imaginary unit). For everyday calculations, only non-negative inputs are valid.
How do I estimate square roots without a calculator?
Find the two perfect squares your number falls between. For √50: √49 = 7 and √64 = 8, so √50 is between 7 and 8, closer to 7. A better estimate: 7.07.