javascript float to integer w3schools

How do I convert a float number to a whole number in JavaScript?

stackoverflow.com › questions › 596467 › how-do-i-convert-a-float-number-to-a-whole-number-in-javascript

var intvalue = Math.floor( floatvalue );
var intvalue = Math.ceil( floatvalue ); 
var intvalue = Math.round( floatvalue );

// `Math.trunc` was added in ECMAScript 6
var intvalue = Math.trunc( floatvalue );

Math object reference

Examples

Positive

// value=x        //  x=5          5<x<5.5      5.5<=x<6  

Math.floor(value) //  5            5            5
Math.ceil(value)  //  5            6            6
Math.round(value) //  5            5            6
Math.trunc(value) //  5            5            5
parseInt(value)   //  5            5            5
~~value           //  5            5            5
value | 0         //  5            5            5
value >> 0        //  5            5            5
value >>> 0       //  5            5            5
value - value % 1 //  5            5            5

Negative

// value=x        // x=-5         -5>x>=-5.5   -5.5>x>-6

Math.floor(value) // -5           -6           -6
Math.ceil(value)  // -5           -5           -5
Math.round(value) // -5           -5           -6
Math.trunc(value) // -5           -5           -5
parseInt(value)   // -5           -5           -5
value | 0         // -5           -5           -5
~~value           // -5           -5           -5
value >> 0        // -5           -5           -5
value >>> 0       // 4294967291   4294967291   4294967291
value - value % 1 // -5           -5           -5

Positive - Larger numbers

// x = Number.MAX_SAFE_INTEGER/10 // =900719925474099.1

// value=x            x=900719925474099    x=900719925474099.4  x=900719925474099.5
           
Math.floor(value) //  900719925474099      900719925474099      900719925474099
Math.ceil(value)  //  900719925474099      900719925474100      900719925474100
Math.round(value) //  900719925474099      900719925474099      900719925474100
Math.trunc(value) //  900719925474099      900719925474099      900719925474099
parseInt(value)   //  900719925474099      900719925474099      900719925474099
value | 0         //  858993459            858993459            858993459
~~value           //  858993459            858993459            858993459
value >> 0        //  858993459            858993459            858993459
value >>> 0       //  858993459            858993459            858993459
value - value % 1 //  900719925474099      900719925474099      900719925474099

Negative - Larger numbers

// x = Number.MAX_SAFE_INTEGER/10 * -1 // -900719925474099.1

// value = x      // x=-900719925474099   x=-900719925474099.5 x=-900719925474099.6

Math.floor(value) // -900719925474099     -900719925474100     -900719925474100
Math.ceil(value)  // -900719925474099     -900719925474099     -900719925474099
Math.round(value) // -900719925474099     -900719925474099     -900719925474100
Math.trunc(value) // -900719925474099     -900719925474099     -900719925474099
parseInt(value)   // -900719925474099     -900719925474099     -900719925474099
value | 0         // -858993459           -858993459           -858993459
~~value           // -858993459           -858993459           -858993459
value >> 0        // -858993459           -858993459           -858993459
value >>> 0       //  3435973837           3435973837           3435973837
value - value % 1 // -900719925474099     -900719925474099     -900719925474099

Answer from moonshadow on Stack Overflow

W3Schools

w3schools.com › js › js_numbers.asp

JavaScript Numbers

Unlike many other programming languages, JavaScript does not define different types of numbers, like integers, short, long, floating-point etc. JavaScript numbers are always stored as double precision floating point numbers, following the ...

Stack Overflow

stackoverflow.com › questions › 596467 › how-do-i-convert-a-float-number-to-a-whole-number-in-javascript

syntax - How do I convert a float number to a whole number in JavaScript? - Stack Overflow

Examples

Positive

// value=x        //  x=5          5<x<5.5      5.5<=x<6  

Math.floor(value) //  5            5            5
Math.ceil(value)  //  5            6            6
Math.round(value) //  5            5            6
Math.trunc(value) //  5            5            5
parseInt(value)   //  5            5            5
~~value           //  5            5            5
value | 0         //  5            5            5
value >> 0        //  5            5            5
value >>> 0       //  5            5            5
value - value % 1 //  5            5            5

Negative

// value=x        // x=-5         -5>x>=-5.5   -5.5>x>-6

Math.floor(value) // -5           -6           -6
Math.ceil(value)  // -5           -5           -5
Math.round(value) // -5           -5           -6
Math.trunc(value) // -5           -5           -5
parseInt(value)   // -5           -5           -5
value | 0         // -5           -5           -5
~~value           // -5           -5           -5
value >> 0        // -5           -5           -5
value >>> 0       // 4294967291   4294967291   4294967291
value - value % 1 // -5           -5           -5

Positive - Larger numbers

// x = Number.MAX_SAFE_INTEGER/10 // =900719925474099.1

// value=x            x=900719925474099    x=900719925474099.4  x=900719925474099.5
           
Math.floor(value) //  900719925474099      900719925474099      900719925474099
Math.ceil(value)  //  900719925474099      900719925474100      900719925474100
Math.round(value) //  900719925474099      900719925474099      900719925474100
Math.trunc(value) //  900719925474099      900719925474099      900719925474099
parseInt(value)   //  900719925474099      900719925474099      900719925474099
value | 0         //  858993459            858993459            858993459
~~value           //  858993459            858993459            858993459
value >> 0        //  858993459            858993459            858993459
value >>> 0       //  858993459            858993459            858993459
value - value % 1 //  900719925474099      900719925474099      900719925474099

Negative - Larger numbers

// x = Number.MAX_SAFE_INTEGER/10 * -1 // -900719925474099.1

// value = x      // x=-900719925474099   x=-900719925474099.5 x=-900719925474099.6

Math.floor(value) // -900719925474099     -900719925474100     -900719925474100
Math.ceil(value)  // -900719925474099     -900719925474099     -900719925474099
Math.round(value) // -900719925474099     -900719925474099     -900719925474100
Math.trunc(value) // -900719925474099     -900719925474099     -900719925474099
parseInt(value)   // -900719925474099     -900719925474099     -900719925474099
value | 0         // -858993459           -858993459           -858993459
~~value           // -858993459           -858993459           -858993459
value >> 0        // -858993459           -858993459           -858993459
value >>> 0       //  3435973837           3435973837           3435973837
value - value % 1 // -900719925474099     -900719925474099     -900719925474099

2 of 16

348

Bitwise OR operator

A bitwise or operator can be used to truncate floating point figures and it works for positives as well as negatives:

function float2int (value) {
    return value | 0;
}

Results

float2int(3.1) == 3
float2int(-3.1) == -3
float2int(3.9) == 3
float2int(-3.9) == -3

Performance comparison?

I've created a JSPerf test that compares performance between:

Math.floor(val)
val | 0 ^{bitwise OR}
~~val ^{bitwise NOT}
parseInt(val)

that only works with positive numbers. In this case you're safe to use bitwise operations well as Math.floor function.

But if you need your code to work with positives as well as negatives, then a bitwise operation is the fastest (OR being the preferred one). This other JSPerf test compares the same where it's pretty obvious that because of the additional sign checking Math is now the slowest of the four.

Note

As stated in comments, BITWISE operators operate on signed 32bit integers, therefore large numbers will be converted, example:

1234567890  | 0 => 1234567890
12345678901 | 0 => -539222987

Videos

01:30

YouTube

Understanding JavaScript Conversion: From Integer to Float - YouTube

July 25, 2024

08:13

YouTube

ParseFloat Method JavaScript - YouTube

How to Use parseInt and parseFloat - YouTube

Javascript | converting Float to Integer - YouTube

March 4, 2022

youtube.com

How do I convert a float number to a whole number in JavaScript?

February 4, 2023

19:52

YouTube

Who Broke JavaScript Floating Point Numbers? [Intermediate Tutorial] ...

June 17, 2022

View all

Delft Stack

delftstack.com › home › howto › javascript › javascript float to int

How to Convert a Float Number to Int in JavaScript | Delft Stack

February 2, 2024 - This tutorial lists out various ways to in JavaScript to convert a floating point number to an integer.

GeeksforGeeks

geeksforgeeks.org › javascript › how-to-convert-a-float-number-to-the-whole-number-in-javascript

How to Convert a Float Number to the Whole Number in JavaScript? - GeeksforGeeks

July 11, 2025 - // float value is 4.59; let x = 4.59; let z = Math.ceil(x); console.log("Converted value of " + x + " is " + z); ... Round a number to its nearest integer.

Code Highlights

code-hl.com › home › javascript › tutorials

5 Easy Ways to Convert JavaScript Float to Int | Code Highlights

June 4, 2024 - The bitwise OR operator can also convert a float to an integer by truncating the decimal part. ... All these methods are compatible with major web browsers, including Chrome, Firefox, Safari, Edge, and Internet Explorer. This ensures that your code will run smoothly across different environments. In this tutorial, we explored five simple methods to convert a JavaScript float to an int:

Rip Tutorial

riptutorial.com › float to integer

JavaScript Tutorial => Float to Integer

To convert a float to an integer, JavaScript provides multiple methods.

Byby

byby.dev › js-float-to-int

How to convert float to integer in JavaScript

You can use various methods that either round, truncate, or parse the float value. Depending on your specific use case, you can choose the most appropriate method: Using Math.trunc(). This method returns the integer part of a number by removing any fractional digits.

W3Schools

w3schools.com › jsref › jsref_parsefloat.asp

JavaScript parseFloat() Method

W3Schools offers free online tutorials, references and exercises in all the major languages of the web. Covering popular subjects like HTML, CSS, JavaScript, Python, SQL, Java, and many, many more.

Find elsewhere

Google Bing Mojeek

W3Schools

w3schools.com › js › js_number_methods.asp

JavaScript Number Methods

The methods above are not number methods. They are global JavaScript methods. The Number() method can be used to convert JavaScript variables to numbers:

Javascripts

javascripts.com › convert-floats-to-integers-in-javascript

How to Convert Floats to Integers in JavaScript

June 23, 2023 - Discover easy techniques to convert floats to integers in JavaScript! Breakdown of methods, code snippets, and clear explanations for beginners and pros alike.

TutorialsPoint

tutorialspoint.com › how-do-i-convert-a-float-number-to-a-whole-number-in-javascript

How do I convert a float number to a whole number in JavaScript?

In the above output users can see that Math.trunc() method has removed the decimal part and Math.round() method has rounded the number to nearest integer. In this approach, we will use the parseInt() method. The parseInt() method extracts the whole number from the float number or string in ...

W3docs

w3docs.com › javascript

How to Convert a Float Number to Whole Number in JavaScript

There are various easy methods to convert float number to the whole number in JavaScript. Let’s discuss each of them and see examples. Here are several built-in functions used for rounding. The math.floor unction rounds the number passed as parameter to its nearest integer in downward direction:

Tutorial Republic

tutorialrepublic.com › faq › how-to-convert-a-float-number-to-a-whole-number-in-javascript.php

How to Convert a Float Number to a Whole Number in JavaScript

Topic: JavaScript / jQueryPrev|Next · You can use the trunc() method to get the integer part of a number by removing any fractional digits. This method was added in ECMAScript 6 and supported by the latest browsers such as Chrome, Firefox, ...

MDN Web Docs

developer.mozilla.org › en-US › docs › Web › JavaScript › Reference › Global_Objects › parseFloat

parseFloat() - JavaScript | MDN

It stops at the n character, and treats the preceding string as a normal integer, with possible loss of precision. If a BigInt value is passed to parseFloat(), it will be converted to a string, and the string will be parsed as a floating-point number, which may result in loss of precision as well.

reddit.com › r/programmeranimemes › hey javascript, can you turn my float into int properly?

[Mature Content] r/ProgrammerAnimemes on Reddit: Hey JavaScript, can you turn my float into int properly?

February 3, 2022 - If you want float to int, you have to use Math.round() or something.

W3Schools

w3schools.com › jsref › jsref_parseint.asp

JavaScript parseInt() Method

The parseInt method parses a value as a string and returns the first integer. A radix parameter specifies the number system to use: 2 = binary, 8 = octal, 10 = decimal, 16 = hexadecimal. If radix is omitted, JavaScript assumes radix 10.

Stack Overflow

stackoverflow.com › questions › 14540398 › why-does-javascript-use-base-10-floating-point-numbers-according-to-w3schools

Why does JavaScript use base 10 floating point numbers (according to w3schools)? - Stack Overflow