Hreflang Language Code Validator
An hreflang language code validator verifies that international alternate tags adhere to official ISO standards. Language subtags must follow two-letter ISO 639-1 formatting, and optional regional subtags must follow two-letter ISO 3166-1 alpha-2 formatting, ensuring search engines recognize localized market targeting.
Language Code Input
Enter individual tags or a list of hreflang codes (one per line).
Code Validation Breakdown
Evaluation against ISO 639-1 language and ISO 3166-1 alpha-2 territory standards.
| Submitted Tag | Status | Standard Formatted Tag | Target Details | Recommendation |
|---|
What is a Hreflang language code validator and when should you use it?
The Hreflang Language Code Validator is a technical compliance utility designed to verify international language and regional country subtags against official ISO specifications. Search engines like Google enforce strict formatting rules when processing hreflang annotations. Under the standardized BCP 47 language tag framework, the primary subtag must represent a valid two-letter ISO 639-1 language code (e.g. "en" for English, "es" for Spanish, "de" for German). If regional targeting is required, an optional secondary subtag representing a two-letter ISO 3166-1 alpha-2 country code must be appended with a hyphen (e.g. "en-US" for United States English or "en-GB" for British English). Common developer mistakes—such as using an underscore ("en_US"), specifying only a country code ("US"), using unofficial territory codes ("en-UK" instead of "en-GB"), or entering three-letter language acronyms—invalidate the annotation and cause search engines to ignore localized signals entirely. This tool allows webmasters to validate single codes or batch audit entire lists against an authoritative dictionary of 140+ ISO languages and 240+ ISO countries. To optimize your broader multi-market setup, generate XML sitemap feeds using the Hreflang XML Sitemap Generator, verify reciprocal links with the Hreflang Return Tag Validator, plan your domain hierarchy with the International URL Structure Planner, review international requirements via the Multilingual SEO Checklist Generator, and structure regional URLs using the Country Targeting URL Mapper. In addition, eliminate configuration errors with the Hreflang Conflict Detector, compare localized SERP snippets using the Multilingual Meta Tag Comparator, inspect fallback routing with the X-Default Hreflang Checker, and prevent de-indexing using the International Canonical Conflict Checker. For foundational technical SEO workflows, explore our Hreflang Tag Generator, Hreflang Checker, XML Sitemap Generator, and Technical SEO Audit Tools categories.
How do you use it?
- Type an individual hreflang code or paste a list of codes (one per line) into the validator input.
- Optionally click "Load Sample Codes" to test valid combinations alongside frequent international errors.
- Click "Validate Language Codes" to evaluate syntax, ISO language matching, and territory codes.
- Review the validation summary cards detailing valid codes, syntax errors, and unknown country/language tags.
- Inspect the detailed results table displaying detected language, assigned country, formatting, and correction advice.
- Copy corrected, standards-compliant hreflang tags directly into your site templates or XML sitemaps.
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Result interpretation & practical applications
When evaluating the output of the Hreflang language code validator, review the parsed metrics against your specific site architecture. Outputs are formatted for direct implementation into your HTML source, web server configuration, or Google Search Console audit files.
Always inspect generated values for contextual nuance. Automated tools highlight structural patterns, but manual verification confirms that technical directives align with your overarching SEO strategy.
Technical rules and limitations
- ISO 639-1 Primary Tag: The first subtag must be a recognized 2-letter lowercase ISO language code.
- ISO 3166-1 Secondary Tag: The optional region subtag must be an uppercase 2-letter country code.
- Hyphen Separator Rule: Subtags must be separated by a hyphen (-). Underscores (_) and slashes (/) are strictly invalid.
- No Country-Only Tags: Declaring only a country code (e.g. hreflang="US" or hreflang="FR") is invalid and rejected by search engines.
Common mistakes and troubleshooting
- Using "en-UK" for Great Britain instead of the official ISO 3166-1 alpha-2 code "en-GB".
- Using "uk" as a territory tag when "uk" is officially reserved for the Ukrainian language.
- Using underscores like "en_US" derived from programming locale standards rather than standard BCP 47 hyphens.
- Entering country codes without language codes, such as declaring hreflang="AU" instead of hreflang="en-AU".
No tool can promise how a search engine will crawl, index, or rank your pages. This tool generates and validates code against documented technical specifications; you determine where to deploy it, and you should always test changes on staging environments first. Google publishes extensive guidelines in Search Central on evaluating third-party SEO tools and advice. Learn more about our technical testing standards on our about us page, or explore full site audits on our pricing page.
Related free tools & workflows
Browse all International & Multilingual SEO Tools →Technical SEO Audit Workflows
Indexability & Crawling
Redirects & HTTP Headers
Authoritative Technical Documentation & Standards
This tool executes logic aligned with official technical documentation and search engine webmaster standards:
- W3C Language Tags specification
W3C: Language Tags in HTML and XML
Primary engineering source and technical documentation.
- IANA Language Subtag Registry reference
IANA: Language Subtag Registry Standards
Primary engineering source and technical documentation.
Hreflang Language Code Validator questions
Is "en-UK" a valid hreflang code in Google Search? ↓
No! The United Kingdom's official ISO 3166-1 alpha-2 country code is "GB". Google requires "en-GB" for British English. Using "en-UK" is invalid and will trigger an error in Google Search Console.
Can I use a region code without a language code in hreflang? ↓
Never. Hreflang requires a language code first. You can declare a language by itself (e.g. "es" for all Spanish speakers worldwide), but you cannot declare a country by itself (e.g. "MX" is invalid; it must be "es-MX").
Are script subtags like zh-Hant and zh-Hans supported? ↓
Yes. Search engines support 4-letter ISO 15924 script codes when targeting script variations, such as "zh-Hant" (Traditional Chinese) and "zh-Hans" (Simplified Chinese), with optional regional additions like "zh-Hans-CN".
Is this tool free? ↓
Yes. It is completely free to use and requires no registration or subscription.
Does this tool visit my website or store my files? ↓
No. It executes entirely in your local browser runtime. Your inputs and results are never stored or logged on our servers.
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