JavaScript

# Difference Between toFixed() and toPrecision() in JavaScript

Javascript provides two methods to get the precise value in scientific or financial data to round the numbers. These are called toFixed() and toPrecision() methods.

The toFixed() rounds the numbers and returns a value before the decimal point and includes the digits after it. However, the toPrecision() rounds the whole number and returns a value before and after the decimal point as per parameter. This post describes the difference between toFixed() and toPrecision() in JavaScript, with the following outcomes:

– How does toFixed() method work in JavaScript

– How does toPrecision() method work in JavaScript

– Difference between toFixed() and toPrecision()

## How does toFixed() method work in JavaScript

The toFixed() method starts to count after the decimal point and rounds the number to a specific length as specified by the user.

Syntax

The syntax of toFixed() is given as follows:

number.toFixed(n)

Here, the ‘number’ represents a variable. While ‘n’ is a parameter that represents the number of decimals.

The toFixed() returns a string with or without decimal representation.

### Example: How to Round a number to 10 decimals using the toFixed() method

The toFixed() method rounds the number after the decimal point according to the provided length.

This example shows how it works.

let num = 1.16379;

console.log(num.toFixed(10));

In the above code, we took a random number ‘1.16379’ and rounded it using the toFixed() method. We put the parameter value ‘10’

This method rounds the numbers after the decimal point according to the given input  It is noticed that the toFixed() method has rounded the original value and 0’s are added to fulfil the specified length.

## How does toPrecision() method work in JavaScript

The toPrecision() method considers the whole number including the digits before as well as after the decimal point. To create a specific length, the nulls and decimal points are added according to need.

Syntax

The syntax of toPrecision() is given as follows:

number.toPrecision(n)

Here, the number represents a variable. 0’s are added if the specified number exceeds the decimal number length.

n’ is the total length of digits.

toPrecision() method rounds the whole number before and after the decimal point to a specified length.

### Example: How to round a number to a specified length using toPrecision() method

The toPrecision() method rounds a number before and after the decimal point and formats it according to the specified length. This example shows the working of this method.

let num = 32.3015;

console.log(num.toPrecision(2));

console.log(num.toPrecision(5));

console.log(num.toPrecision(10));

In the above code, a random number ‘32.3015’ is taken and applied to the formation using the toPrecision() method. To format the number, we took the three-parameter values respectively. This code represents the number formatting with the specified length of ‘2, 5, 10’. After putting the parameter value ‘2’, the toPrecision considered only two digits after it. While with the value of ‘5’, the five digits before and after the decimal point of a specified length. Similarly, when the parameter’s value is ‘10’, the four ’0’s’ are added to complete the 10-digit length.

## Difference between toFixed() and toPrecision()

As we know, the toFixed() method count starts after the decimal point and rounds the number including the digit after it. While the toPrecioson() count starts before the decimal point and rounds the whole number before and after the decimal point.

Here, we will explain the difference between the toFixed() method and the Precision() method by using the following example.

num = 3.37158

console.log(num.toFixed(9));

num = 3.37158

console.log(num.toPrecision(9));

In this code, a random number ‘3.37158’ is specified to the parameters using tofixed() and to Precision() methods. We have passed the same parameter value, ‘9’, to both methods. In the case of the toFixed() value, the output showed that the function rounds the value to ‘9’ after the decimal point putting the four ’0’s’. While in another case, the toPrecision() function rounds the specified value according to the given parameter before and after the decimal point.

## Conclusion

The toFixed() and toPrecision() methods round the number to get accurate value in scientific or financial data. This post intends to provide the difference between the toFixed() and toPrecision() methods in JavaScript. For a better understanding, we have also enlightened the importance and the usages of both methods separately. 