How to round a float value to N decimal places in Ruby

In this tutorial, we are going to learn about How to round a float value to N decimal places in Ruby using the round() method.

Consider, we have a float value like this.

num  = 12.1421

Now, we need to format the above float value to 3 decimal places like this 12.142.

Using the round() method

To round a number to N decimal places in Ruby, we can use the round() method by passing N as a argument to it.

N is number of decimal places we need to round the float value.

The round() method takes the number of digits as argument and formats the number into the mentioned decimal places. By default the round() method removes the fractional part.

Let’s see an example:

num  = 12.1421

puts num.round(2)

Output:

12.142

In the example, above we have passed 3 as an argument to the round() method. So that it rounds a float value to 3 decimal places.

Similarly, if you want round a float value to 2 decimal places just pass the 2 as an argument to the round() method.

Here is an example of how to round a float value to 2 decimal places:

num  = 12.1421

puts num.round(2)

Output:

12.14