Need to find the square root of a number? Our free Square Root Calculator gives you the answer instantly. Enter any non-negative number to calculate its square root, and use the result for math homework, measurements, formulas, or everyday calculations.
Square Root Calculator
How to Use the Square Root Calculator
Using the Square Root Calculator is simple. Enter a number in the input box and click Calculate Square Root. The calculator will immediately show the square root of the number.
You can enter whole numbers as well as decimal numbers. The calculator accepts zero and other non-negative values.
What Is a Square Root?
A square root is a number that, when multiplied by itself, gives the original number.
For example:
5 × 5 = 25
Therefore:
√25 = 5
The symbol √ is called the square root symbol, or radical sign.
Square Root Formula
The square root of a number can be written as:
√x = y
This means that:
y × y = x
For example:
√64 = 8
because:
8 × 8 = 64
Square Root Examples
Example 1: Square Root of 25
The square root of 25 is:
√25 = 5
because:
5 × 5 = 25
Example 2: Square Root of 100
√100 = 10
because:
10 × 10 = 100
Example 3: Square Root of 144
√144 = 12
because:
12 × 12 = 144
Example 4: Square Root of 2
Not every square root is a whole number.
For example:
√2 ≈ 1.4142135624
The calculator gives a decimal approximation for numbers like this.
Perfect Squares
A perfect square is a number that has a whole-number square root.
Some common perfect squares are:
- 1 → √1 = 1
- 4 → √4 = 2
- 9 → √9 = 3
- 16 → √16 = 4
- 25 → √25 = 5
- 36 → √36 = 6
- 49 → √49 = 7
- 64 → √64 = 8
- 81 → √81 = 9
- 100 → √100 = 10
Knowing common perfect squares can make some calculations easier to do without a calculator.
Square Root of a Decimal
Square roots can also be calculated for decimal numbers.
For example:
√0.25 = 0.5
because:
0.5 × 0.5 = 0.25
The same basic rule applies to decimals as it does to whole numbers.
Can You Find the Square Root of a Negative Number?
The calculator is designed for real-number calculations, so it does not return a real square root for a negative number.
For example, there is no real number that can be multiplied by itself to produce −9.
In more advanced mathematics, negative square roots can be represented using imaginary numbers, but that is outside the scope of this calculator.
Square Root vs. Squaring a Number
Squaring and finding a square root are opposite operations.
For example:
6² = 36
and:
√36 = 6
When you square 6, you get 36. When you find the square root of 36, you get 6.
Frequently Asked Questions
What is the square root of a number?
The square root is a number that produces the original number when multiplied by itself.
What is the square root of 0?
The square root of 0 is 0.
Can I calculate the square root of a decimal?
Yes. You can enter decimal numbers into the calculator.
What is a perfect square?
A perfect square is a number whose square root is a whole number, such as 16, 25, 36, or 100.
Can I calculate the square root of a negative number?
This calculator only works with real-number square roots, so negative numbers are not accepted.
How is a square root written?
A square root is commonly written using the √ symbol. For example, the square root of 49 is written as √49.
Related Calculators
You may also find these math calculators useful: