Subdomain to Root Domain Converter
A subdomain to root domain converter turns entries like blog.example.co.uk into the main registrable domain, example.co.uk. Paste hostnames or URLs and this free tool shows a mapping table and a unique list of root domains. It uses the Public Suffix List, so multi-part endings such as .co.uk and .com.au are handled correctly.
Unique Root Domains
Input to Root Domain Mapping
| Input | Host | Ending (Suffix) | Root Domain | Status |
|---|
Unique Root Domains Frequency
| Root Domain | Count |
|---|
What is a subdomain to root domain converter and when should you use it?
Simply cutting the last two parts of a domain gives the wrong answer for endings such as .co.uk, where it would return co.uk. The Public Suffix List is a public list of such endings, and this tool uses it to find the real main domain. This matters when you decide whether to disavow a whole site with a domain: line. To get domains from full URLs first, use the URL to Domain Extractor. Extracting root domains ensures that your disavow directives and outreach lists apply at the registrable domain level. Before normalizing subdomains, extract hostnames from URL lists with the URL to Domain Extractor and eliminate duplicate records with the Backlink List Deduplicator or Line Sorter and Deduplicator. For disavow workflows, generate compliant files using the Disavow File Generator, verify formatting via the Disavow File Validator, and sanitize messy lists with the Disavow File Cleaner. Additionally, evaluate link toxicity with the Toxic Backlink Checker, inspect TLD patterns with the Backlink TLD Distribution tool, analyze anchor texts via the Anchor Text Distribution Analyzer, and clean Search Console data with the Search Console Links CSV Cleaner.
How do you use it?
- Paste hostnames or URLs, one per line.
- Press Convert.
- Check the mapping table.
- Download the unique root domains.
Working on a comprehensive technical audit? Browse all free SEO tools to discover the next step in your workflow, or contact our technical support team if you require a specialized custom utility.
Result interpretation & practical applications
When evaluating the output of the subdomain to root domain converter, 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
- 100% Client-Side Processing: Processing occurs in browser memory using native Web APIs.
- Zero Server Storage: Inputs, outputs, and intermediate states are never saved to our database.
- Standards Compliant: Rules adhere to published Google Search Central and W3C web standards.
Common mistakes and troubleshooting
- Cutting the last two parts and getting co.uk instead of example.co.uk.
- Expecting IP addresses to have a root domain.
- Disavowing a whole root domain when only one subdomain was a problem.
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 Advanced SEO, Migration & Quality Assurance 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:
- Public Suffix List official specification
Public Suffix List: Specification and Guidelines
Primary engineering source and technical documentation.
- Google Search Central domain architecture guide
Google Search Central: Managing Multi-Regional Sites
Primary engineering source and technical documentation.
Subdomain to Root Domain Converter questions
What is the Public Suffix List? ↓
A public list of domain endings under which people can register names, such as .com and .co.uk.
Why is my entry unchanged? ↓
It is an IP address, or its ending is not in the list.
When was the list updated? ↓
The date is shown below the tool.
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.
Ready for the next step in your audit?
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