--- title: Optimize the common cases | daily.dev description: When formatting numbers in Rust, adding fast paths for small values (-99 to 99) can dramatically reduce latency. Using hard-coded branches for single-digit and... canonical: https://daily.dev/posts/optimize-the-common-cases-d9ueelqrp twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Optimize the common cases | daily.dev og:description: When formatting numbers in Rust, adding fast paths for small values (-99 to 99) can dramatically reduce latency. Using hard-coded branches for single-digit and... og:url: https://daily.dev/posts/optimize-the-common-cases-d9ueelqrp og:image: https://api.daily.dev/og/posts/d9ueelQrp.png og:image:alt: Optimize the common cases 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. # Optimize the common cases **[Sylvain Kerkour](https://daily.dev/sources/kerkour)** · 1 min read · 0 upvotes · 0 comments ## Summary When formatting numbers in Rust, adding fast paths for small values (-99 to 99) can dramatically reduce latency. Using hard-coded branches for single-digit and two-digit cases in the stdx/format_number library brings formatting time from 2–10 nanoseconds down to ~700 picoseconds — under a nanosecond — by bypassing loop machinery and SIMD logic entirely. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### How fast can Rust format small integers like single or two-digit numbers? With dedicated fast paths for single-digit and two-digit numbers, Rust can format integers in the -99 to 99 range in approximately 700 picoseconds — under one nanosecond. Without these branches, even SIMD-accelerated number formatting takes 2–10 nanoseconds. The optimization works by bypassing loop machinery entirely and using a precomputed lookup table for two-digit values. _Rust developers squeezing nanoseconds out of hot paths share techniques like these on daily.dev._ ## Similar posts on daily.dev - [Faster floating point math with Rust’s new API](https://daily.dev/posts/faster-floating-point-math-with-rust-s-new-api-zyoed6fm9) · Lobsters · 0 upvotes · 0 comments - [Rust language adds algebraic floating-point methods](https://daily.dev/posts/rust-language-adds-algebraic-floating-point-methods-jimyxkos8) · InfoWorld · 1 upvotes · 0 comments - [&&&&&&&&&&&&&&str](https://daily.dev/posts/str-ek7vtalze) · Lobsters · 0 upvotes · 0 comments --- Tags: [#performance](https://daily.dev/tags/performance), [#rust](https://daily.dev/tags/rust) [View this post on daily.dev](https://daily.dev/posts/optimize-the-common-cases-d9ueelqrp) ```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":"Optimize the common cases","url":"https://daily.dev/posts/optimize-the-common-cases-d9ueelqrp","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/optimize-the-common-cases-d9ueelqrp"},"datePublished":"2026-08-11T08:55:29.630Z","dateModified":"2026-08-11T09:39:49.975Z","description":"When formatting numbers in Rust, adding fast paths for small values (-99 to 99) can dramatically reduce latency. 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Without these branches, even SIMD-accelerated number formatting takes 2–10 nanoseconds. The optimization works by bypassing loop machinery entirely and using a precomputed lookup table for two-digit values. Rust developers squeezing nanoseconds out of hot paths share techniques like these on daily.dev."}}]} ```