Floor function to get highest lower integer of a number in JavaScript

Enter a number

We can use math function floor to get the floor of a number or the largest integer which is equal to or lower than the given number.

So by using floor we can get the floor value of an number.

Here is the syntax.

Math.floor(number)

Let us try with some examples. $Floor ceil Math functions$


document.write (Math.floor(11.257)); // output 11
document.write ("<br>----<br>");

document.write (Math.floor(1.56)); // output 1
document.write ("<br>----<br>");


document.write (Math.floor(-3.564)); // output -4
document.write ("<br>----<br>");


document.write (Math.floor(-7.164)); // output -8
document.write ("<br>----<br>");

Not numeric or blank inputs

We will get output as NaN for all blank and non-numeric inputs.

document.write(Math.floor()); // Output NaN 
document.write("<br>");
document.write(Math.floor('abc')); // Output NaN 
document.write("<br>");

Difference between floor() and round()

Math.floor() always returns previous lower side integer, where Math.round can return integer value higher or lower than the input value.
Example :

<script>
document.write(Math.round(5.42)+'<br>'); // Output 5
document.write(Math.floor(5.42)+'<br>'); // Output 5

document.write(Math.round(5.67)+'<br>'); // Output 6
document.write(Math.floor(5.67)+'<br>'); // Output 5

document.write(Math.round(-5.42)+'<br>'); // Output -5
document.write(Math.floor(-5.42)+'<br>'); // Output -6

document.write(Math.round(-5.67)+'<br>'); // Output -6
document.write(Math.floor(-5.67)+'<br>'); // Output -6
</script>

Next higher value of decimal number by ceil
JavaScript Math Reference

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Makwana Parvez	11-02-2019
very good and explaination of example is very nice

Floor function to get just lower integer of a number

Not numeric or blank inputs

Difference between floor() and round()