javascript math float - Brave Search

How can I deal with floating point number precision in JavaScript? [duplicate]

stackoverflow.com › questions › 1458633 › how-can-i-deal-with-floating-point-number-precision-in-javascript

From the Floating-Point Guide:

What can I do to avoid this problem?

That depends on what kind of calculations you’re doing.

If you really need your results to add up exactly, especially when you work with money: use a special decimal datatype.

If you just don’t want to see all those extra decimal places: simply format your result rounded to a fixed number of decimal places when displaying it.

If you have no decimal datatype available, an alternative is to work with integers, e.g. do money calculations entirely in cents. But this is more work and has some drawbacks.

Note that the first point only applies if you really need specific precise decimal behaviour. Most people don't need that, they're just irritated that their programs don't work correctly with numbers like 1/10 without realizing that they wouldn't even blink at the same error if it occurred with 1/3.

If the first point really applies to you, use BigDecimal for JavaScript or DecimalJS, which actually solves the problem rather than providing an imperfect workaround.

Answer from Michael Borgwardt on Stack Overflow

stackoverflow.com › questions › 1458633 › how-can-i-deal-with-floating-point-number-precision-in-javascript

How can I deal with floating point number precision in JavaScript? - Stack Overflow

From the Floating-Point Guide:

What can I do to avoid this problem?

That depends on what kind of calculations you’re doing.

If you really need your results to add up exactly, especially when you work with money: use a special decimal datatype.

If you just don’t want to see all those extra decimal places: simply format your result rounded to a fixed number of decimal places when displaying it.

If you have no decimal datatype available, an alternative is to work with integers, e.g. do money calculations entirely in cents. But this is more work and has some drawbacks.

Note that the first point only applies if you really need specific precise decimal behaviour. Most people don't need that, they're just irritated that their programs don't work correctly with numbers like 1/10 without realizing that they wouldn't even blink at the same error if it occurred with 1/3.

If the first point really applies to you, use BigDecimal for JavaScript or DecimalJS, which actually solves the problem rather than providing an imperfect workaround.

I like Pedro Ladaria's solution and use something similar.

function strip(number) {
    return (parseFloat(number).toPrecision(12));
}

Unlike Pedros solution this will round up 0.999...repeating and is accurate to plus/minus one on the least significant digit.

Note: When dealing with 32 or 64 bit floats, you should use toPrecision(7) and toPrecision(15) for best results. See this question for info as to why.

w3schools.com › js › js_numbers.asp

JavaScript Numbers

Real numbers (floating-point): float (32-bit), double (64-bit). Javascript numbers are always double (64-bit floating point).

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September 18, 2019

JavaScript Tip: Avoiding Problems with Decimal Math - YouTube

mathjs.org › docs › datatypes › numbers.html

math.js | an extensive math library for JavaScript and Node.js

Math.js uses the built-in JavaScript Number type. A Number is a floating point number with a limited precision of 64 bits, about 16 digits. The largest integer number which can be represented by a JavaScript Number is +/- 9007199254740992 (+/- 2^53). Because of the limited precision of floating ...

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

parseFloat() - JavaScript - MDN Web Docs

The parseFloat() function parses a string argument and returns a floating point number. function circumference(r) { return parseFloat(r) * 2.0 * Math.PI; } console.log(circumference(4.567)); // Expected output: 28.695307297889173 console.log(circumference("4.567abcdefgh")); // Expected output: ...

library.fridoverweij.com › docs › floating_points_in_js

Floating points in JavaScript

March 23, 2025 - Programming languages may even ... data types: number (floating points) and the more recent addition to the language BigInt (bignums). The number data type represents floating point numbers and is the general numeric data type for both integers and fractions....

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

Math.floor() - JavaScript - MDN Web Docs

The Math.floor() static method always rounds down and returns the largest integer less than or equal to a given number.

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

Math.fround() - JavaScript - MDN Web Docs

July 10, 2025 - console.log(Math.fround(5.5)); // Expected output: 5.5 console.log(Math.fround(5.05)); // Expected output: 5.050000190734863 console.log(Math.fround(5)); // Expected output: 5 console.log(Math.fround(-5.05)); // Expected output: -5.050000190734863 ... The nearest 32-bit single precision float representation of doubleFloat. JavaScript uses 64-bit double floating-point numbers internally, which offer a very high precision.

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shecodes.io › athena › 24061-what-is-a-float-in-javascript

[JavaScript] - What is a float in JavaScript? - SheCodes | SheCodes

Learn about the float data type in JavaScript and how it's used to represent numbers with a fractional part or very large/small numbers.

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

Math - JavaScript - MDN Web Docs

Returns the nearest single precision float representation of the input.

patrickkarsh.medium.com › why-math-is-hard-in-javascript-floating-point-precision-in-javascript-41706aa7a89d

Math is Hard in JavaScript: Floating-Point Precision in JavaScript | by Patrick Karsh | Medium

November 24, 2023 - This article delves into the common errors encountered in JavaScript’s floating-point arithmetic, providing examples to illustrate these quirks and offering insight into their underlying causes.

reddit.com › r/javascript › [askjs] how do you deal with floats in production apps?

r/javascript on Reddit: [AskJS] How do you deal with floats in production apps?

August 13, 2022 -

We all know the 0.1 + 0.2 = 0.30000000000000004 and the precision issues with Javascript floats (IEEE-754). These problems are immediately visible (and applicable) to nearly all application which has number/floats (even simple calculation via JS) on both frontend and backend with Node.js/Deno.js/Bun.js etc.

How do you deal with the fact that the floating point, which is the result of a calculation, is represented exactly and is saved correctly in DB/REST api/front end etc.

It depends why you need it. If you want to calculate money then you should use dinero or implement Money class yourself. Treating money as float is easiest way to big trouble

You can use .toPrecision js function. any precision 16 and under will calculate .1 + .2 without the classical trailing 4 bug and you can clean it up after to remove the extra zeros if you have them. for more info check out; https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/toPrecision

codemag.com › article › 1811041 › JavaScript-Corner-Math-and-the-Pitfalls-of-Floating-Point-Numbers

JavaScript Corner: Math and the Pitfalls of Floating Point Numbers

August 31, 2022 - JavaScript performs arithmetic calculations with floating point numbers in a manner consistent with other programming languages. What's a developer to do? Does this mean if you have mathematical operations to perform, JavaScript is useless? Of course not. The real issue is floating point/double ...

geeksforgeeks.org › javascript › how-to-add-float-numbers-using-javascript

Add float numbers using JavaScript - GeeksforGeeks

November 13, 2025 - JavaScript · let val = ... · Given two or more numbers, to sum up the float numbers. Use parseFloat() and Math.round() method to get the desired output....

geeksforgeeks.org › javascript › floating-point-number-precision-in-javascript

Floating point number precision in JavaScript - GeeksforGeeks

July 11, 2025 - It is a double-precision format where 64 bits are allocated for every floating point. The displaying of these floating values could be handled using these methods: Table of Content ·

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

Math.round() - JavaScript - MDN Web Docs

console.log(Math.round(0.9)); // Expected output: 1 console.log(Math.round(5.95), Math.round(5.5), Math.round(5.05)); // Expected output: 6 6 5 console.log(Math.round(-5.05), Math.round(-5.5), Math.round(-5.95)); // Expected output: -5 -5 -6

Adripofjavascript

adripofjavascript.com › blog › drips › avoiding-problems-with-decimal-math-in-javascript.html

Avoiding Problems with Decimal Math in JavaScript - A Drip of JavaScript

In JavaScript all numbers are IEEE 754 floating point numbers. Due to the binary nature of their encoding, some decimal numbers cannot be represented with perfect accuracy. This is analagous to how the fraction 1/3 cannot be accurately represented with a decimal number with a finite number ...

gist.github.com › lsloan › f8c5ab552545ee968cca

JavaScript floating point math bug example · GitHub

for (i = 0.00; i <= 1.00; i = +((i + 0.01).toPrecision(2))) { // Note the final-expression in the for-loop limits decimal places, // overcoming float errors from adding 0.01 j = i * 100; if (Math.round(j) != j) { console.log('Multiplcation error:', i, j); } }

modernweb.com › frontend development › what every javascript developer should know about floating points

What Every JavaScript Developer Should Know About Floating Points | Modern Web - Web3, Business & Technology

May 5, 2023 - Imagine doing basic mathematics like 0.1 + 0.2, and the answer returns 0.2625! Fortunately, the floating point specification that ECMAScript uses specifies up to 52 mantissa, so the rounding errors are quite small – the specification specifically details the expected rounding errors for most numbers.

JavaScript.info

javascript.info › tutorial › the javascript language › data types

December 18, 2024 - They “read” a number from a string until they can’t. In case of an error, the gathered number is returned. The function parseInt returns an integer, whilst parseFloat will return a floating-point number:

geeksforgeeks.org › javascript › how-to-format-a-float-in-javascript

How to Format a Float in JavaScript? - GeeksforGeeks

July 12, 2025 - // Define the float value let n = 6.56759; let roundValue = Math.round(n); console.log("Math.round(n) =", roundValue); ... The JavaScript Math.round() method rounds a number to the nearest integer.