Square Roots on Calculator
To find a square root on most calculators, press √ and then the number (or the number then √ on older models). On a phone, rotate to landscape for the √ key. Or just type the number below: you'll get the decimal root, the simplified radical form and the cube root.
- √72
- 8.485281374
- Simplified radical
- 6√2
- Perfect square?
- No
- Cube root
- 4.160167646
- Square (x²)
- 5184
Steps
- 72 = 36 × 2
- √72 = √36 × √2 = 6√2
Worked example
Example: √72
- Find the largest perfect-square factor: 72 = 36 × 2
- √72 = √36 × √2 = 6√2
- ≈ 8.485281374
√72 = 6√2 ≈ 8.4853.
Formula
√(a × b) = √a × √b
√x = x^(1/2)
Simplify a radical by pulling out the largest perfect square factor. Negative numbers have imaginary square roots: √−9 = 3i.
Frequently asked questions
How do I do a square root on an iPhone calculator?
Turn the phone sideways to open the scientific layout, type the number and tap √x.
How do I square a number on a calculator?
Press x² after the number, or multiply it by itself. The result above also shows x².
What is the square root of 2?
About 1.414213562. It's irrational, so its decimals never end or repeat.
Last reviewed October 17, 2026 · Calculations run in your browser; nothing you enter is sent to a server.