# How to Use Scientific Notation in JavaScript

Scientific notation is a compact and convenient way to represent very large or very small numbers in a standardized format. It is widely used in scientific and engineering applications to handle numbers that are difficult to work within their standard decimal forms.

JavaScript provides built-in support for scientific notation, making it easier for developers to manipulate and display such numbers accurately and efficiently.

## Scientific Notation in JavaScript

Floating-point values are an essential part of numerical representation in computing. In various programming languages, including JavaScript, these values can be represented using e-notation.

In JavaScript, the e-notation format typically consists of an integer, a number, or a floating-point followed by `e` or `E`, which denotes the power of 10 by which the base value is multiplied. Note that `10e1` represents `10` multiplied by `10^1` (which is `100`), while `10e-1` stands for `10` multiplied by `10^(-1)` (which equals `1`).

Here’s an example:

``````let numberInScientificNotation = 6.0221e23;  // Avogadro's number
console.log(numberInScientificNotation);
``````

Output:

``````6.0221e+23
``````

JavaScript’s default behavior is to convert any floating-point value with at least six trailing zeros into an e-notation. This simplifies the representation and facilitates the efficient handling of numerical operations.

``````const largeNumber = 1234567890123456789012345678901234567890;
const smallNumber = 0.00000000123456789;

console.log(largeNumber);  // Output: 1.2345678901234568e+39
console.log(smallNumber);  // Output: 1.23456789e-9
``````

Let’s have an example to further understand the application of e-notation in JavaScript:

``````console.log(10e1 * 10e-1);
console.log(10e2 * 10e-2);
console.log(1e12 * 1e-12);
``````

In the example above, we’ve demonstrated three calculations where we multiply `10^1` by `1/10^1`, `10^2` by `1/10^2`, and `1 * 10^12` by `1 * 1/10^12`.

When you run this code, the output will be:

``````100
100
1
``````

Demo here

## Convert Numbers to Scientific Notation in JavaScript

To convert a number to scientific notation, you can use the `toExponential()` method available for numbers in JavaScript. This method allows you to specify the desired number of decimal places for the coefficient.

The syntax for this method is as follows:

``````number.toExponential([decimalDigits])
``````

Parameters:

• `number`: The number you want to convert to exponential notation.
• `decimalDigits` (optional): An integer specifying the number of digits after the decimal point. It represents the number of digits in the resulting string.

It returns a string representing the given number in scientific notation.

Example:

``````let num = 123456.789;

console.log(num.toExponential());

console.log(num.toExponential(2));
``````

Output:

``````1.23456789e+5
1.23e+5
``````

In the first example, the `toExponential()` method is called without specifying `decimalDigits`, so it uses the default behavior and displays the number in scientific notation.

In the second example, `decimalDigits` is specified as 2, so the resulting string displays the number in scientific notation with two digits after the decimal point.

## Parse Scientific Notation in JavaScript

If you have a string representing a number in scientific notation and you want to parse it into a JavaScript number, you can use `parseFloat()` or `Number()`.

The `parseFloat()` function is commonly used to parse a string and extract a floating-point number. It accurately handles scientific notation within the provided string.

Here’s a simple example demonstrating how to use `parseFloat()`:

``````const scientificNotationString = '6.022e23';
const parsedNumber = parseFloat(scientificNotationString);

console.log(parsedNumber);
``````

Output:

``````6.022e+23
``````

In this example, the `parseFloat()` function parses the string `'6.022e23'` and converts it into the JavaScript number `6.022e23`.

On the other hand, the `Number()` function in JavaScript is another way to parse a string into a numeric value, handling scientific notation effortlessly. It can convert a wide range of representations into valid JavaScript numbers, including scientific notation.

Here’s an example:

``````const scientificNotationString = '1.602e-19';
const parsedNumber = Number(scientificNotationString);

console.log(parsedNumber);  // Output: 1.602e-19
``````

Output:

``````1.602e-19
``````

In this example, the `Number()` function successfully parses the string `'1.602e-19'` and converts it into the JavaScript number `1.602e-19`.

## Conclusion

Scientific notation is a crucial tool for representing extremely large or small numbers in a concise and standardized way. JavaScript provides built-in support for scientific notation, making it convenient for developers to work with such numbers in their applications.

Understanding how to express, convert, and parse numbers in scientific notation in JavaScript is essential for anyone dealing with numerical data and calculations in their code.

Shraddha is a JavaScript nerd that utilises it for everything from experimenting to assisting individuals and businesses with day-to-day operations and business growth. She is a writer, chef, and computer programmer. As a senior MEAN/MERN stack developer and project manager with more than 4 years of experience in this sector, she now handles multiple projects. She has been producing technical writing for at least a year and a half. She enjoys coming up with fresh, innovative ideas.