If you run more than one version of your site - a UK version and a US version, say, or English and French - Google needs to know which one to show to whom. Without that, US searchers can land on your UK pages with pound prices and UK spelling, or Google can treat your versions as duplicates and pick one at random.
Hreflang is how you tell it.
What hreflang is
Hreflang is an HTML attribute that tells search engines which language - and optionally which country - a page is for, and where its alternative versions live.
<link rel="alternate" hreflang="en-gb" href="https://example.com/uk/pricing/" />
<link rel="alternate" hreflang="en-us" href="https://example.com/us/pricing/" />
<link rel="alternate" hreflang="x-default" href="https://example.com/pricing/" />
Each version of the page lists every version, including itself.
When you need it
- You have the same content for different countries in the same language (UK and US English, for example).
- You have translated versions of pages.
- You have country-specific versions with different prices, currencies or legal information.
You don't need hreflang for a single-market, single-language site.
How to write hreflang values
- Language comes first, in ISO 639-1 format: en, fr, de.
- Country is optional and comes second, in ISO 3166-1 alpha-2 format: gb, us, ie.
- The UK is gb, not uk. en-uk is one of the most common hreflang errors.
- x-default is the fallback for anyone who doesn't match a listed version, often your global or language-selector page.
Three ways to implement it
| Method | How it works | Best for |
|---|---|---|
| HTML head tags | <link> tags in the head of each page | Most sites with a manageable number of versions |
| XML sitemap | Alternates listed for each URL in the sitemap | Large sites, or where editing templates is hard |
| HTTP headers | Hreflang sent in the response header | Non-HTML files such as PDFs |
Pick one method per site and stick to it. Mixing methods makes errors harder to find.
The rules that matter
- Return tags. If the UK page points to the US page, the US page must point back. Missing return tags are the most common reason Google ignores hreflang.
- Self-reference. Each page lists itself as well as its alternatives.
- Canonicals. Each version should canonicalise to itself. A US page that canonicalises to the UK page tells Google to ignore the US version.
- Indexable URLs only. Point hreflang at live, indexable pages - not redirects, 404s or noindexed pages.
- Absolute URLs. Use full URLs including https.
Common mistakes
- Using en-uk instead of en-gb.
- Missing return tags after adding a new market.
- Canonical tags pointing all versions at one "master" page.
- Hreflang pointing at redirected URLs after a migration.
- Automatic geo-redirects that stop Google's crawler, which mostly crawls from the US, from ever seeing your UK pages.
- Localised versions that are identical apart from currency, which Google may still fold together.
How to check it's working
- Crawl the site with an SEO crawler that reports hreflang errors, such as missing return tags and non-indexable targets.
- Check Search Console for international targeting issues and which version is being shown in each country.
- Search from each market (with location settings or a VPN) and see which version appears.
- Re-check after every migration, new market launch or major template change.
Hreflang is only part of international SEO
Hreflang tells Google which version to show. It doesn't make a version rank. For that, each market needs content built around its own searches and links from sources trusted in that market. Our international SEO strategy guide covers how UK companies rank in the US, and our UK to US SEO service is built around it.
Frequently asked questions
Is hreflang a ranking factor?
Not directly. It helps Google show the right version to the right searcher, which protects the rankings and conversions each version earns.
Do I need hreflang for UK and US English?
Yes, if you have separate UK and US versions of the same content. Without it, Google may show the wrong one or treat them as duplicates.
What is x-default?
The fallback version for searchers who don't match any language or country you've listed - often a global page or a country selector.
Should I use hreflang in the HTML or the sitemap?
Either works. HTML tags are simpler for smaller sites; sitemaps are easier to manage for large sites with many versions.
The takeaway
Hreflang is simple in principle and easy to break in practice. Use en-gb, not en-uk, include return tags and self-references, keep canonicals self-referencing, and re-check after every change.
Expanding into the US or Europe? Book a 30-minute call and we'll check your international setup before it costs you rankings.
Selling into the US? See our international SEO agency work for UK companies entering the US.
Nomada Digital is a B2B SEO and AI search agency. The views here are practitioner-level and based on real client data.