Rounding Numbers in JavaScript

A very common question while dealing with Math methods in JavaScript is to round numbers. JavaScript provides 3 rounding methods: round(), ceil() and floor()

round() – rounds a number up if decimal part is >= .5, else rounds down

ceil() - rounds a number up to the nearest whole number and removes decimal

floor() – rounds a number down to the nearest whole number and removes decimal

Here’s an example:

<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>Math Rounding by DevCurry.com</title>
</head>
<body>
<script type="text/javascript">
function callRounding(num) {
document.write("Original value: " + num + "</br>");
document.write("Using round(): " + Math.round(num) + "</br>");
document.write("Using ceil(): " + Math.ceil(num) + "</br>");
document.write("Using floor(): " + Math.floor(num) + "</br>");
}
</script>
<input id="btn1" type="button" value="Example 1"
onClick="callRounding(2.12)" />
<input id="btn2" type="button" value="Example 2"
onClick="callRounding(2.62)" />
<input id="btn3" type="button" value="Example 3"
onClick="callRounding(-2.62)" />
</body>
</html>


OUTPUT

image

See a Live Demo



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About The Author

Suprotim Agarwal
Suprotim Agarwal, Developer Technologies MVP (Microsoft Most Valuable Professional) is the founder and contributor for DevCurry, DotNetCurry and SQLServerCurry. He is the Chief Editor of a Developer Magazine called DNC Magazine. He has also authored two Books - 51 Recipes using jQuery with ASP.NET Controls. and The Absolutely Awesome jQuery CookBook.

Follow him on twitter @suprotimagarwal.

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