Square Root Calculator

The square root of any number — including negative inputs.

Quick answer: Calculate square roots online. Find principal roots for any number, complete with imaginary root support for negative numbers.

Square root42
Squared check1,764

computed locally — nothing leaves your browser

Take the square root of any number to 8-digit precision, with honest handling of negative inputs (imaginary results) instead of an error.

How it works

  1. Type the number you want to find the root of.
  2. The calculator computes the principal root out to 8 decimal places.
  3. Copy the precise real or imaginary answer.

Frequently asked questions

Why does my calculator error on negatives?

Basic calculators only handle real numbers. Negative numbers have imaginary roots, shown here with the i notation.

Is the answer exact?

Perfect squares are exact (√1764 = 42). Most roots are irrational and shown rounded to 8 digits.

What is a principal root?

Both +42 and −42 square to 1764; the principal (default) root is the positive one.

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