Square Root Calculator — Free Online Tool
Find square roots, cube roots and nth roots of any number. · No signup · Works on mobile
100% private: your data is processed in your browser. Nothing is uploaded to our servers.
How to use the square root calculator
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Enter the number you want the root of.
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Choose the root: square (2), cube (3), or type any n.
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See the decimal result, perfect-power check, and simplified radical form.
What does this tool do?
This free square root calculator finds the square root, cube root, or any nth root of a number instantly. It shows the decimal answer to 10 digits, tells you whether the number is a perfect square, and displays the simplified radical form (e.g. √72 = 6√2).
How does the square root calculator work?
Roots are computed with high-precision floating point (x^(1/n)). For simplification, the tool factors out the largest perfect-square divisor: √72 = √(36×2) = 6√2. Negative inputs return real cube roots but flag square roots as imaginary (√−9 = 3i).
Frequently Asked Questions
How do I simplify a square root like √72?
Factor out the largest perfect square: 72 = 36 × 2, so √72 = √36 × √2 = 6√2 ≈ 8.485. Working through perfect squares (4, 9, 16, 25, 36…) as divisors is the standard method — this calculator does it automatically.
What is the square root of a negative number?
No real number squared gives a negative, so √−9 is not real — it equals 3i using the imaginary unit i (where i² = −1). Cube roots of negatives are real though: ∛−27 = −3, because (−3)³ = −27. The calculator handles both cases correctly.
Is the square root calculator really free?
Yes — 100% free with no hidden charges, trial limits, or premium tiers for core features. You don't need to create an account or enter an email address. The site is supported by non-intrusive display ads, which keeps every tool free for everyone.
Is my data private when using the square root calculator?
Completely. The square root calculator runs entirely in your browser using JavaScript — nothing you type or upload is sent to our servers. When you close the tab, your data is gone. This makes it safe for confidential documents, financial figures, and personal information.
Does the square root calculator work on mobile phones?
Yes. The square root calculator is built mobile-first and works on any phone or tablet with a modern browser — iPhone (Safari), Android (Chrome), and everything in between. The layout adapts to small screens, so buttons and inputs stay easy to tap on a 375px-wide display.
Do I need to install anything to use the square root calculator?
No. The square root calculator works directly in your web browser — no downloads, no extensions, no signup. Just open the page, use the tool, and get your result instantly. It works on Windows, macOS, Linux, ChromeOS, iOS, and Android.