What Is Domain Authority?
If you’ve spent any time researching expired domains, you’ve seen the term Domain Authority (DA) thrown around constantly. “DA 40+” listings on domain auctions. Tools that show DA as the headline metric. SEO blogs telling you to only buy domains above a certain DA score.
But what does DA actually mean? And more importantly — can you trust it when evaluating an expired domain?
What Is Domain Authority?
Domain Authority is a score developed by Moz, ranging from 1 to 100, that predicts how likely a website is to rank in search engine results. The higher the score, the more likely the site is to rank well.
It’s calculated using dozens of factors, but the biggest contributors are:
- The number of unique websites linking to the domain (linking root domains)
- The quality and authority of those linking sites
- The overall link profile diversity
Important: DA is a Moz metric. It is not a Google metric. Google does not use DA in its ranking algorithm. However, because DA correlates well with real-world ranking ability, it has become a widely used proxy for domain quality.
Why DA Matters for Expired Domains
When a domain expires and gets picked up by a new owner, all of the backlinks pointing to it still exist — at least initially. This means the new owner inherits the domain’s existing link equity, which is reflected in its DA score.
A DA 40 expired domain, for example, has enough link equity that a new site built on it may rank faster than a brand-new domain would. This is the core reason people buy expired domains for SEO.
Why You Can’t Trust DA Alone
Here’s the problem: DA can be misleading.
1. Spam backlinks inflate DA. A domain with 500 backlinks from low-quality PBNs (Private Blog Networks) or spam sites can show a DA of 30–40, but those links have no real SEO value and may actually hurt you.
2. DA drops after a domain expires. When a domain goes offline, sites that linked to it may eventually remove the links. DA is a snapshot in time — it doesn’t tell you how fast the link profile is decaying.
3. DA doesn’t reflect penalties. A domain can have a high DA and still be manually penalized by Google. You’d never know from the DA score alone.
The Right Way to Use DA
Think of DA as a starting point, not a final verdict. Here’s a smarter evaluation framework:
| Metric | What to Look For |
|---|---|
| DA Score | 20+ is a baseline; 40+ is strong |
| Spam Score | Keep it under 5%; above 10% is risky |
| Blacklist Status | Must be clean |
| Real Age (Wayback) | Older real age = more trust |
| Backlink Quality | Check if linking sites are real, relevant |
How to Check DA on an Expired Domain
You can check DA for free using our Expired Domain Analyzer. It pulls the Moz DA score alongside the spam score, blacklist status, and archive history — giving you the full picture in one report.
The Bottom Line
DA is a useful signal, but it’s only one piece of the puzzle. A domain with DA 50 and a spam score of 30% is far less valuable than a domain with DA 25 and a spotless history. Always evaluate DA in context and never buy a domain based on DA alone.