--- title: Why JavaScript Floating Point Math Breaks Your App (And... description: JavaScript uses IEEE 754 double-precision floating point for all numbers, meaning decimals like 0.1 + 0.2 can't be represented exactly in binary. This causes... canonical: https://daily.dev/posts/why-javascript-floating-point-math-breaks-your-app-and-how-to-fix-it--0nl3mfyyi twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Why JavaScript Floating Point Math Breaks Your App (And How to Fix It) | daily.dev og:description: JavaScript uses IEEE 754 double-precision floating point for all numbers, meaning decimals like 0.1 + 0.2 can't be represented exactly in binary. This causes... og:url: https://daily.dev/posts/why-javascript-floating-point-math-breaks-your-app-and-how-to-fix-it--0nl3mfyyi og:image: https://api.daily.dev/og/posts/0nl3MfYYI.png og:image:alt: Why JavaScript Floating Point Math Breaks Your App (And How to Fix It) og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Why JavaScript Floating Point Math Breaks Your App (And How to Fix It) **[Sergio Lema](https://daily.dev/sources/sergiolema-dev)** · 5 min read · 1 upvotes · 0 comments ## Summary JavaScript uses IEEE 754 double-precision floating point for all numbers, meaning decimals like 0.1 + 0.2 can't be represented exactly in binary. This causes subtle bugs in financial and precision-sensitive code — not just the obvious 0.1 + 0.2 case, but composed calculations like Math.ceil(1.7000000000000002 * 100) / 100 producing 1.71 instead of 1.70. Four practical solutions are covered: using toFixed() only for display output, working in integer cents for monetary values, a scale-round-ceil pattern to neutralize floating point noise in pre-computed floats, and using decimal.js or big.js for complex chained financial calculations. The recommended default for money is integer arithmetic. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Mathematical precision in Javascript](https://daily.dev/posts/mathematical-precision-in-javascript-zwkniwuun) · Chen Hui Jing · 0 upvotes · 0 comments - [How to Understand the Safe Integer Limit in JavaScript](https://daily.dev/posts/how-to-understand-the-safe-integer-limit-in-javascript-4vq0h3lnj) · freeCodeCamp · 5 upvotes · 2 comments - [Why You Should Never Use Floating Point for Money](https://daily.dev/posts/why-you-should-never-use-floating-point-for-money-mf4k3pznd) · Sergio Lema · 17 upvotes · 6 comments - [Why Ruby’s Issue Tracker Still Links to a 1991 Paper About Floating-Point Numbers](https://daily.dev/posts/why-ruby-s-issue-tracker-still-links-to-a-1991-paper-about-floating-point-numbers-vijgzx189) · RUBYLAND · 1 upvotes · 1 comments --- Tags: [#general-programming](https://daily.dev/tags/general-programming), [#javascript](https://daily.dev/tags/javascript) [View this post on daily.dev](https://daily.dev/posts/why-javascript-floating-point-math-breaks-your-app-and-how-to-fix-it--0nl3mfyyi) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Why JavaScript Floating Point Math Breaks Your App (And How to Fix It)","url":"https://daily.dev/posts/why-javascript-floating-point-math-breaks-your-app-and-how-to-fix-it--0nl3mfyyi","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/why-javascript-floating-point-math-breaks-your-app-and-how-to-fix-it--0nl3mfyyi"},"datePublished":"2026-04-06T05:04:33.302Z","dateModified":"2026-10-15T02:22:18.463Z","description":"JavaScript uses IEEE 754 double-precision floating point for all numbers, meaning decimals like 0.1 + 0.2 can't be represented exactly in binary. 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