Looking for JavaScript round to 2 decimal places? JavaScript provides several methods for rounding numbers to a specific number of decimal places.

Rounding numbers can be useful in many programming scenarios, such as financial calculations or formatting data for display.

In JavaScript, you can round numbers to 2 decimal places using built-in methods such as –

  1. toFixed()
  2. Math.round()
  3. Math.floor()
  4. toPrecision()

These methods allow you to round a number to a specific number of decimal places and return the result as a new number.

In this way, you can ensure that your calculations and data display is accurate and consistent.

Method 1: Using the toFixed() method

The toFixed() method returns a string representation of a number that is rounded to a specified number of decimal places.

In our case, we want to round a number to 2 decimal places.


let num = 3.14159;
let roundedNum = num.toFixed(2);  // 3.14 but the type is string

roundedNum = parseFloat(roundedNum);  //change string back to number type

But if you check the type of the variable roundedNum, it will give the type as a string.

Therefore, it is necessary to convert the roundedNum variables to number type again. You can use the parseFloat function in Javascript to do it.

2. Javascript round to 2 decimals using Math.round() method

The Math.round() method rounds a number to the nearest integer. We can use this to round numbers to 2 decimals.

Math.round to 2 decimal places javascript example-


let num = 3.14159;
let multipliedNum = num * 100;              //314.159
let roundedNum = Math.round(multipliedNum); //314
roundedNum = roundedNum / 100;              //3.14

Step 1: Multiply the number by 100 to move the decimal point two places to the right.

Step 2: Use the Math.round() method to round the multiplied number to the nearest integer.

Step 3: Divide the rounded number by 100 to move the decimal point back to its original position.

3. Javascript round to 2 decimal using the Math.floor() method

JavaScript Math.floor() method rounds a number down to the nearest integer.


let num = 3.14159;
let multipliedNum = num * 100;              //314.159
let roundedNum = Math.floor(multipliedNum); //314

roundedNum = roundedNum / 100;              //3.14

Step 1: Multiply the number by 100 to move the decimal point two places to the right.

Step 2: Use the Math.floor() method to round the multiplied number down to the nearest integer.

Step 3: Divide the rounded number by 100 to move the decimal point back to its original position.

Difference between Math.floor() and Math.round() method

Ok, you might think we are doing the same repeated steps. While Math.floor() and Math.round() are used to round numbers in JavaScript, they differ in the way they round numbers.

Math.round() method

Math.round() rounds a number to the nearest integer.

If the fractional part of the number is less than 0.5, it rounds down. Otherwise, it rounds up.

For example, Math.round(3.49) returns 3, and Math.round(3.51) returns 4.

Math.floor() method

Math.floor() rounds a number down to the nearest integer.

It always rounds down, regardless of the fractional part of the number.

For example, Math.floor(3.49) returns 3, and Math.floor(3.51) also returns 3.

In summary, Both methods are useful in different programming scenarios, depending on the desired result.

4. Round to 2 decimal places JavaScript using toPrecision() method

This method returns a string representation of the number with a specified number of significant digits. We can specify the number of decimal places using the toPrecision() method.

After that, we can use parseFloat to change the string back to number type.


let num = 3.14159;
let roundedNumString = num.toPrecision(2); // '3.14'
roundedNum = parseFloat(roundedNumString);     // 3.14

Conclusion

In conclusion, rounding a number to two decimal places is a common operation in many programming scenarios. JavaScript provides several built-in methods to accomplish this task.

The toFixed() method is the easiest way in javascript to round to 2 decimals. It returns a string representation of the number with the specified number of decimal places.

The Math.round() and Math.floor() methods can also be used to round a number to two decimal places. Math.round() rounds the number to the nearest integer, while Math.floor() rounds the number down to the nearest integer.

The toPrecision() method can be used to round a number to a specific number of significant digits, rather than decimal places. This can be useful in scenarios where significant digits are more important than decimal places.

Overall, these methods provide flexibility and options to round to 2 decimals JavaScript, depending on the specific needs of your programming task.