Free Domain List Compare
Compare two domain lists by hostname or registrable root. Find common, missing and unique domains, count occurrences and export each selected set locally.
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How to use the domain list compare
Compare two domain lists by hostname or registrable root. Find common, missing and unique domains, count occurrences and export each selected set locally.
- Paste or import lists A and B. CSV settings apply to both inputs.
- Choose full hostname or root-domain comparison and optional private suffix or Unicode settings.
- Select common domains, A-only, B-only, union or symmetric difference, then process locally.
- Review per-list counts and overlap statistics, inspect rejected entries and export the selected comparison.
When comparing two domain lists saves hours
Marketers, SEO teams and IT staff often hold two lists that should match but do not. You might compare backlink domains from two audit exports, check which customer domains appear in a CRM but not in a mailing platform, or confirm that an allowlist and a firewall export cover the same sites.
Doing this by eye or with spreadsheet formulas gets messy once URLs, subdomains and www prefixes are mixed in. This tool cleans each entry to a domain first and then runs the set comparison, so you see real overlap instead of formatting differences.
Everything runs in your browser, so client lists, vendor lists and internal domains stay on your device while you work.
A worked example with the built-in sample
List A holds https://shop.example.co.uk/products, https://example.com/a and https://bücher.de. List B holds example.com, https://news.example.co.uk/ and example.org. With the default root-domain mode and Common to A and B selected, the result is two rows: example.co.uk and example.com, each with one occurrence in A and one in B.
The statistics show 3 unique domains in A, 3 in B, 2 common, 1 only in A, 1 only in B and a union of 4, so the overlap is 2 divided by 4, or 50 percent. Switch to symmetric difference and you get example.org marked B only and xn--bcher-kva.de marked A only. Change to full hostname mode and only example.com matches, because shop and news are different hosts. The overlap then drops to 20 percent, 1 out of 5.
How root domains and statistics are worked out
In root mode each hostname is reduced to its registrable domain using a bundled public suffix list. That is why shop.example.co.uk becomes example.co.uk rather than co.uk. Shared hosting suffixes such as blogspot.com can be recognized, so separate blogs are not merged into one entry. International names are shown in their ASCII Punycode form unless you turn on Unicode display.
Each list is grouped before comparison, and the result table shows total occurrences, the count in A, the count in B and the membership label. You can filter by suffix, exclude domains and their subdomains, set a minimum occurrence count and sort by name, input order or frequency. Exports are available as TXT, CSV and a full JSON report.
Common mistakes to avoid
Picking the wrong mode is the most frequent error. Use hostname mode when blog.site.com and shop.site.com must be treated as different properties, and root mode when you only care about the organization behind them.
Check the rejected entries before trusting the numbers. Typos such as bad..com or an unknown suffix are left out of the comparison. When importing CSV files, set the right column number, because the CSV settings apply to both lists.
Finally, keep in mind that the union set includes every unique domain once, so it is the right choice when you want to merge two lists without duplicates.
Useful tips and limitations
- Root-domain mode groups different subdomains of the same registrable domain.
- Overlap is intersection divided by union; it is a list comparison statistic, not a domain quality score.
- Sort by highest frequency to spot the domains that appear most often across both sources before you decide which ones to review first.
- Use the Result contains filter to narrow a large comparison to one brand or country suffix before exporting.
Common questions
What does symmetric difference mean in the domain list comparison?
It contains domains found in exactly one of the lists, excluding domains present in both.
Can domain comparison ignore subdomains and www?
Choose root-domain mode to compare registrable roots, or use hostname mode with the separate leading-www removal option.
How many domains can I compare at once?
The tool processes up to 20,000 entries and 2,000,000 characters across both lists combined, and imported text files can be up to 2 MiB each.
Does the overlap percentage use list A as the base?
No. It is the number of common domains divided by the number of unique domains in either list, so both lists count equally.
Will the tool check whether these domains are live?
No. It compares text only and never contacts the listed domains, so a matched domain may still be expired or offline.
Text, local files and results are processed in your browser without AI or uploads. Listed domains, links, email addresses and IPs are not contacted. Save a local export before leaving.