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
// 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
// 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
// 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
Top answer 1 of 16
2261
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
// 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
// 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
// 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
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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 | 0bitwise OR~~valbitwise NOTparseInt(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
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, ...
[SOLVED] typecast float to int in javascript? - Unity Engine - Unity Discussions
A forum search has lead me to think it’s not doable. “as” only works on reference types and Unity doesn’t dig var f1 : float = 3.14; var myVar : int = (int)f1; or var f1 : float = 3.14; var myVar : int = int(f1); If anyone knows a typecast method that work’s I’d appreciate a “how ... More on discussions.unity.com
1
September 18, 2009Convert a Float number to an Int type
I am trying to convert a float number to an integer. The reason is that I want the E8S equivalent of 1 ICP of a value, for example 1.15. This should be 115_000_000, but the function returns 114_000_000. Other values are calculated correctly, for example 1.25 = 125_000_000 or 0.9 = 90_000_000. ... More on forum.dfinity.org
0
June 10, 2024Float is getting converted to either int or string. But we need to pass it as float.
Hi @dchiesa1 , We’re working on a response payload transformation. We’re using javascript to do it as the response payload consists of lots of arrays. Here there’s a field where we receive it as float and we need to pass a float to source systems. But JS is somehow converting the float ... More on googlecloudcommunity.com
2
January 23, 2024How can I convert from float to int without undefined behavior?
Why not do the bounds checking? The behavior you're describing doesn't sound like it will meet the needs of everyone (or every instruction set), so I'd recommend just writing the function that has the instructions and behavior that meets your needs More on reddit.com
16
12
October 17, 2023Videos
00:12
Javascript | converting Float to Integer - YouTube
How do I convert a float number to a whole number in JavaScript?
03:06
How to convert a STRING to FLOAT/INT in JavaScript. - YouTube
06:28
How to Use parseInt in JavaScript | Convert Strings to Integers ...
01:16
How to CONVERT FLOAT TO INT in Unity - YouTube
W3docs
w3docs.com › javascript
How to Convert a Float Number to Whole Number in JavaScript
The parseInt() function parses the string argument and returns an integer of the given radix. ... The ~~ operator rounds a number towards 0 if the operand is a number and it’s not NaN or Infinity. ... The OR operator rounds a number towards 0. ... There are two types of numbers in JavaScript: Regular and BigInt. Regular is also known as “double-precision floating-point numbers”. The math is a built-in object which has properties and methods for mathematical constants and functions.
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.floor(x); console.log("Converted value of " + x + " is " + z); ... Return the smallest integer greater than or equal to a given number.
Unity
discussions.unity.com › unity engine
[SOLVED] typecast float to int in javascript? - Unity Engine - Unity Discussions
September 18, 2009 - A forum search has lead me to think it’s not doable. “as” only works on reference types and Unity doesn’t dig var f1 : float = 3.14; var myVar : int = (int)f1; or var f1 : float = 3.14; var myVar : int = int(f1);…
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?
July 20, 2022 - In this approach, we will use the parseInt() method. The parseInt() method extracts the whole number from the float number or string in JavaScript. The other easiest solution is to get the whole number part from the float number. Users can follow the below syntax to use the parseInt() method.
Internet Computer Developer Forum
forum.dfinity.org › developers
Convert a Float number to an Int type - Developers - Internet Computer Developer Forum
June 10, 2024 - Other values are calculated correctly, for example 1.25 = 125_000_000 or 0.9 = 90_000_000. public func convertFloatToNat(x: Float): async Int { let ONE_ICP_IN_E8S = 100_000_000; Debug.print("convertFloatToNat "#debug_show(x)); let a = ...
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:
Google Developer forums
googlecloudcommunity.com › google cloud › apigee
Float is getting converted to either int or string...
January 23, 2024 - Hi @dchiesa1 , We’re working on a response payload transformation. We’re using javascript to do it as the response payload consists of lots of arrays. Here there’s a field where we receive it as float and we need to pass a float to source systems. But JS is somehow converting the float to int when decimal part contains only zeros.
Reddit
reddit.com › r/zig › how can i convert from float to int without undefined behavior?
r/Zig on Reddit: How can I convert from float to int without undefined behavior?
October 17, 2023 -
I have a float (f32/f64) that I'd like to convert to an int (i32/u32/i64/u64).
The most obvious tool I could use is @intFromFloat(). But that invokes undefined behavior if the float is outside the range of the int.
What I'd like is to convert the float to an int without causing undefined behavior. I'm fine with the resulting integer having an unspecified value in this case. If the float is NaN, inf, or outside the range of the integer, the int could have any arbitrary, garbage value. That'd be fine.
What's the most efficient way to do this in Zig? Is there something like @intFromFloat() that doesn't cause nasal demons, but also avoids adding bounds checking or branching instructions?
I could use inline assembly and use fcvtzs (armv8) and cvttss2si (x86_64) but I don't want to inhibit the optimizer, which inline assembly often does.
Top answer 1 of 4
11
Why not do the bounds checking? The behavior you're describing doesn't sound like it will meet the needs of everyone (or every instruction set), so I'd recommend just writing the function that has the instructions and behavior that meets your needs
2 of 4
8
IIRC There are functions in the maths module that can do that or return error on stuff like not in range. Also you should think about how you want to round the number.
Codemia
codemia.io › knowledge-hub › path › how_do_i_convert_a_float_number_to_a_whole_number_in_javascript
How do I convert a float number to a whole ...
Enhance your system design skills with over 120 practice problems, detailed solutions, and hands-on exercises
Julia Programming Language
discourse.julialang.org › general usage
Convert float type array to Int - General Usage - Julia Programming Language
July 31, 2021 - Hi, I have been trying to convert the array type to Int for a = [3.0 2.0;2.0 4.0;7.0 8.0] I tried convert function and used loops but have not received the required output: a = [3 2;2 4;7 8] Thanks
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.
W3Schools
w3schools.com › js › js_number_methods.asp
JavaScript Number Methods
The valueOf() method is used internally in JavaScript to convert Number objects to primitive values.
W3Schools
w3schools.com › js › js_numbers.asp
JavaScript Numbers
JavaScript numbers are always stored as double precision floating point numbers, following the international IEEE 754 standard. This format stores numbers in 64 bits, where the number (the fraction) is stored in bits 0 to 51, the exponent in bits 52 to 62, and the sign in bit 63:
MDN Web Docs
developer.mozilla.org › en-US › docs › Web › JavaScript › Reference › Global_Objects › Number › parseFloat
Number.parseFloat() - JavaScript | MDN
The Number.parseFloat() static method parses an argument and returns a floating point number. If a number cannot be parsed from the argument, it returns NaN.
W3Schools
w3schools.com › jsref › jsref_parsefloat.asp
JavaScript parseFloat() Method
at() charAt() charCodeAt() codePointAt() concat() constructor endsWith() fromCharCode() includes() indexOf() isWellFormed() lastIndexOf() length localeCompare() match() matchAll() padEnd() padStart() prototype repeat() replace() replaceAll() search() slice() split() startsWith() substr() substring() toLocaleLowerCase() toLocaleUpperCase() toLowerCase() toString() toUpperCase() toWellFormed() trim() trimEnd() trimStart() valueOf() JS Typed Arrays · Int8Array Uint8Array Uint8ClampedArray Int16Array Uint16Array Int32Array Uint32Array BigInt64Array BigUint64Array Float16Array Float32Array Float64Array JS Typed Reference
MDN Web Docs
developer.mozilla.org › en-US › docs › Web › JavaScript › Reference › Global_Objects › Number
Number - JavaScript | MDN
Number values represent floating-point numbers like 37 or -9.25. The Number constructor contains constants and methods for working with numbers. Values of other types can be converted to numbers using the Number() function.
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 - The case of negative float numbers like Math.floor(-23.97) may seem confusing, but the function rightly converts the value to the next lower integer, -24.