Ignoring character limits can wreck your product’s UXHow to create clear, functional, and scalable content without compromising layout or localizationFREEPIKHave you ever written a piece of UI text — say, a button label, heading, or field name — only to find out later that it broke the layout?Or received a translated string (hello, German!) that no longer fits inside its component?If so, you’ve already experienced firsthand how crucial character limitations are in digital products.It’s an essential — but often underestimated — practice that can make or break the user experience of the product you’re helping to build.First things first: what are character limits?Character limits refer to the maximum number of characters a piece of UI text (like buttons, form fields, error messages, titles, etc.) can have within a given interface component.But here’s the key: these limits aren’t arbitrary. And they’re not just about counting letters.In multilingual digital products, the available space for text is limited — and it varies wildly between languages. Translated strings can expand or shrink, directly impacting the layout and usability of your interface.Languages like German or Russian often require more space to convey the same message as English or Portuguese. If that expansion isn’t anticipated, you may end up with truncated text, broken layouts, or even a loss of meaning.That’s why character limits aren’t just technical constraints — they’re a strategic UX writing tool. They’re defined based on:Technical factors: like the actual visual space availableLinguistic factors: such as text expansion/contraction in different languagesUsability concerns: including legibility and message clarityThe goal? Ensure your content fits within the real constraints of the UI, while staying readable, accessible, and adaptable across multiple languages and cultures.The world (and its languages) are bigger than your Figma fileIf your product is localized, you’ve probably seen this: the same string in different languages can take up drastically different amounts of space.Portuguese tends to be more verbose than English. German loves long compound words. Chinese can say a lot in just a few characters.So yes — strings shrink or stretch depending on the linguistic and grammatical structure of the target language.Take a simple button like “Buy now”:→ German: “Jetzt kaufen” or even “Jetzt sofort kaufen”→ Russian: Купить сейчас@ WikipediaSome translations can expand up to 35% compared to the original string. That means your neat little “Buy now” button could morph into a monstrous block of text in German — breaking layout and harming usability.And this isn’t just about aesthetics. Long strings in small spaces confuse the eye, increase cognitive load, and degrade the overall navigation experience.Character limits help us:Prioritize clarityImprove legibilityPromote smoother interaction — especially on mobile, where real estate is scarceWhen product, design, content, and engineering teams align around well-defined, documented limits, it becomes much easier to:Set up automated validations during content creation or translationUse localization tools that flag overflowsAvoid last-minute fixes for layout-breaking contentWhy UX Writers need to master thisUX Writers are responsible for functional copy within the context of the interface. That means:Connecting content with available visual spaceCollaborating with design, engineering, and localization teamsMaking writing decisions that work not just in the source language, but in 5, 10, or 25 othersTesting and iterating copy based on actual UI validationsMastering character limits means your copy will fit, function, and communicate — no matter the language.If we ignore character limits, the result is content that doesn’t fit, doesn’t work, and doesn’t communicate — hurting both usability and user trust.But for UX Writers, working with limits isn’t a creative block — it’s a sharpening tool.When space is tight, writing has to be:Precise, so eliminate fluffTask-oriented, prioritizing strong verbs and nounsFocused on immediate action or understanding, ensuring every word earns its place in the user journeyWell-written short copy avoids redundancy, prioritizes impactful words, and ensures every term serves a clear purpose in the user journey.UX Writers are advocates — not just for clarity, but for visual harmony, cultural relevance, and global consistency.Good writing works within constraints. Great UX writing balances clarity, visual consistency, and cultural nuance.That’s not cutting copy randomly — it’s writing to function. Writing within character limits is writing with intent.So… how do you calculate character limits?Unless you’re a psychic, don’t guess.The most accurate way to set limits is with this formula:MAX LIMIT = (COMPONENT’S USABLE WIDTH) / (AVERAGE CHARACTER WIDTH)Let’s break it down:Usable width = total component width minus padding and marginsAverage character width depends on the font used (e.g., Arial 16px ≈ 9px per character)This gives you a solid baseline for your source language (usually English or Portuguese). Then, apply a 20–35% expansion margin to accommodate longer translations.Example:If your component is 260px wide and uses Arial at 16px:→ 260 / 9 = ~29 characters in PT-BR→ With 35% expansion: 29 * 1.35 = ~39 characters for GermanBoom. You’ve just saved your layout in every language.Without defined limits, text can:OverflowBreak componentsOverlap with other UI elementsOr fail to render altogetherWriters and designers must protect the integrity of the interface by agreeing on sensible limits.One size doesn’t fit allOne universal character limit won’t cut it. Each UI element has its own constraints, so each one needs tailored limits.According to WCAG guidelines, text lines should max out at 80 characters (or 40 for Asian scripts) to remain legible.@ ZeroheightRough benchmarks for Portuguese or English UI (but adjust by case!):Buttons (very limited horizontal space): 20–30 charactersHeadings & Titles (more visual weight): 30–60 charactersError messages (must be brief yet informative): up to 70 charactersForm labels & menu items (must be consistent and scannable): 15–25 charactersTooltips & descriptions (complementary info): up to 120 charactersThese aren’t hard rules, but starting points. They show how you should factor in a component’s utility and space when setting its limits.If a component can’t support what it needs to communicate within the limit, adjust either the text or the UI.Content never lives outside the interface — if it doesn’t fit, it doesn’t work.If the UI doesn’t support the amount of text needed, consider either: adjusting the copy or adjusting the design.Tools that can helpSome tools can make your life easier when defining and managing character limits — especially when collaborating across larger teams.Localization Platforms: Smartcat, SimpleLocalize, Lokalise→ Set per-key limits and receive overflow alerts.Online Counters: QuillBot, Twaino, Calculatodo→ Quick character checks across languages.Traditional Tools: Word, Google Docs, Excel→ Useful for detailed manual validation or bulk review.Common mistakes (and how to avoid them)Avoiding these classic traps helps ensure your product’s content remains consistent and user-friendly. When setting character limits, steer clear of these pitfalls:1. Ignoring text expansion in other languagesDesigning for the source language alone won’t cut it. Always leave room to grow.2. Focusing only on character count — not width20 characters ≠ 20 characters in every language. Some letters and scripts take more space.3. Using one-size-fits-all limitsEach UI element has different constraints. Buttons ≠ error messages. Use tailored limits per component type.4. Not testing with real translationsIf you don’t test with actual localized content, you’re just guessing.Personal file5. Overlooking cultural differencesLocalization ≠ direct translation. Cultural context, tone, and idioms matter. This is where machine translations often fall short.For example:German/Russian: longer expressions → layout issuesChinese/Japanese: short but dense → spacing & legibility challengesArabic/Hebrew: RTL languages → layout mirroringHindi, Khmer: complex scripts → special typographic needs6. Skipping intelligent truncationTruncated text can confuse — or offend. If truncation is necessary, define how it happens, plan for truncation points (e.g., “…” + tooltip).Best practices: what to doNow that you know what not to do, here’s what you should be doing:Calculate based on real component widthsInclude a 20–35% buffer for expansionCreate a reference table with limits by component and languagePersonal fileTest real content across languagesUse tools that flag overflowPlan truncation (e.g., “…”, “More” links, or tooltips)Document limits for developers, translators, designersRespect WCAG for accessibility (≤80 characters per line, letter spacing ≥ 0.12x font size)Validate input with scripts or regex at the entry pointWatch out for “danger” characters (quotes, emojis, etc.)Always localize — not just translate. Prioritize tone, context, clarityCharacter limits aren’t blockers. They’re UX tools.They go beyond aesthetics — theyre at the intersection of functionality, readability, accessibility, and internationalization.By ensuring your content fits, adapts, and reads well across languages and devices, UX Writers play a critical role in crafting scalable, inclusive, and high-performing experiences.When you apply these guidelines based on real-world calculations, practical testing, and localization best practices, you help deliver responsive, user-friendly interfaces across every language and market.Backed by smart calculations, real-world tests, and localization best practices, your product’s UI will work beautifully — for everyone.ReferencesA Importância da Competência Cultural na Tradução e Interpretação, Bureau Works.Length limit in translation to make your UI localization easier, Smartcat.Introducing: Character limit in translations, SimpleLocalize.Tackling text expansion and contraction in localization, Poeditor.A formula for defining maximum character lengths, UX Content Collective.Best Practices for Writing Global-Ready Content for Localization, Phrase.Ignoring Character Limits Can Wreck Your Product’s UX was originally published in UX Collective on Medium, where people are continuing the conversation by highlighting and responding to this story.