What is it?
The Square Root Calculator finds the square root of a number. It also shows the cube root, the square, the cube and, if you want, any other root.
Who is it for?
Students, builders finding sides from areas, and anyone needing roots quickly.
How to use it
- Type the Number.
- For a 4th, 5th or other root, type that number in nth root (optional).
- Read the square root, cube root, square and cube; they change as you type.
The answer appears as you type; there is no Calculate button. Tap Copy result to copy it, or Share on WhatsApp to send it.
Negative numbers
- A negative number has no real square root: √−16 is 4i (imaginary). The calculator says so.
- Cube roots of negatives are fine: ∛−27 = −3. The same goes for any odd root.
Simplifying roots by hand
Take out square factors: √72 = √(36 × 2) = 6√2 ≈ 8.485. The Prime Number Checker shows the factors you need.
Uses
- Side of a square plot from its area: a 900 sq ft plot is 30 ft × 30 ft.
- Diagonals and distances (with the Pythagoras Calculator).
- Standard deviation and other statistics use square roots.
Results are rounded to show about 10 significant digits.
Worked examples
- √144 = 12; √2 ≈ 1.41421.
- ∛125 = 5; ∛−8 = −2.
- The 4th root of 81 = 3 (because 3⁴ = 81).
- A square plot of 2,500 sq ft is √2500 = 50 ft on each side.
Estimating by hand
√50 lies between √49 = 7 and √64 = 8, closer to 7: about 7.07. This quick check catches typing mistakes.
Errors and how to fix them
- Negative number: square roots of negatives aren’t real numbers; odd roots are fine.
Open the tool: Square Root Calculator
Still stuck?
Contact support. Tell us which tool or page you were using, what you tapped, what you saw, and your phone or computer and browser (for example: Android phone, Chrome). We reply by email.
Questions, or an error not listed here?
Tell us in the comments: what you were doing, the exact message you saw, and your device and browser. We read every comment and add new fixes to this article.