What Does Domain Authority Mean?

If you have ever run your website through an SEO tool, or had an email offering to "boost your DA", you will have come across Domain Authority. It is one of the most quoted numbers in SEO, and one of the most misunderstood.

This guide explains what Domain Authority is, how it is calculated, what counts as a good score and, most importantly, how much attention a small or medium-sized business should give it.

Domain Authority (DA) is a score created by the SEO software company Moz. It runs from 1 to 100 and is designed to predict how likely a website is to rank in search results compared with other websites. The higher the score, the stronger Moz judges the site's link profile to be.

The key word is compared. Moz describes DA as a comparative metric, so a single score on its own tells you very little. It becomes useful when you put it next to the scores of the sites you compete with in search.

No. Domain Authority is a Moz metric, not a Google one, and Google does not use it to rank pages. Moz itself says DA is not a Google ranking factor and has no effect on search results.

Google has said the same thing repeatedly. In 2023, Google's John Mueller said that Google does not use scores from third-party SEO tools, whether they claim to measure a website's authority or how spammy it is.

So why does DA matter at all? Because the things it tries to measure, mainly the quantity and quality of links pointing at your website, do overlap with things Google cares about. DA is a rough outside estimate, built by a third party from its own index of the web. It can be a helpful signpost, but it is not the destination.

Moz calculates DA using a machine learning model that relies mainly on backlink data from its own web index. The inputs include the number of unique websites linking to you (often called linking root domains or referring domains) and the quality of those links.

Moz updated the model in March 2019, a change it called Domain Authority 2.0. The update added factors such as Moz's own Spam Score and patterns in link quality, and it changed scores for most websites. If you read older articles that mention MozRank or MozTrust as the ingredients of DA, they describe the earlier version.

Two features of the scale are worth understanding:

• It is logarithmic. Moz explains that it is much easier to move from 20 to 30 than from 70 to 80. Each point near the top of the scale takes far more links to earn.
• It is relative. If very large websites gain lots of new links, the scale can shift and other sites' scores may fall, even if nothing changed on those sites.

There is no universal good score. A new website starts at 1, and sites with huge numbers of quality links, such as major news organisations or Wikipedia, sit near the top. Most local businesses will have far lower scores than national brands, and that is normal.

A more useful question is how your score compares with the websites that rank for the searches you want to win. Moz's own example is that a DA of 30 could be strong in one industry and weak in another. If you are a plumber in Loughborough, compare yourself with other local plumbers, not with national comparison sites.

Scores move for reasons that have nothing to do with your rankings. According to Moz, common causes include:

• Moz's index picking up more or fewer of the sites that link to you
• Gaining or losing links
• Changes in the scores of very large sites, which shift the scale for everyone else
• Links from places that do little for search rankings
• Updates to how Moz calculates the score

New links can also take time to appear in Moz's index, so a fresh piece of coverage may not show in your score straight away. A drop in DA does not mean Google has demoted your website. Check your actual search performance before worrying.

Moz also publishes Page Authority (PA), which uses the same idea for individual pages rather than whole domains. It is worth remembering that Google ranks pages, not websites, so a strong, well-linked page on a modest site can outrank a weak page on a big one.

Moz is not the only company with a score like this. The two you are most likely to see are:

• Domain Rating (DR) from Ahrefs. Ahrefs describes DR as a measure of the relative strength of a website's backlink profile on a scale from 0 to 100. Ahrefs says it is purely link-based and does not account for link spam.
• Authority Score from Semrush. Semrush's Authority Score runs from 1 to 100 and combines link data, estimated organic traffic and checks for signs of manipulation.

Each tool uses its own index and its own formula, so the same website will get different numbers from each one. Pick one, use it consistently and compare like with like.

Used carefully, DA can help with a few practical jobs:

• Benchmarking. Compare your score with the sites ranking above you to get a feel for the gap in link strength.
• Spotting trends. A steady rise over a year or two usually reflects genuine link growth.
• Judging link opportunities. When deciding where to spend time on outreach or PR, a score can help you prioritise, alongside relevance and real readership.

What DA should not do is become a target in its own right. Chasing the number leads businesses towards paid links, link swaps and low-quality directories. Google's spam policies treat buying links that pass ranking credit and excessive link exchanges as link spam, and they can harm a site's visibility.

Be wary of anyone selling "DA boosts". A score can be inflated without any improvement in search performance, and you could end up paying for links that put your website at risk.

The reliable way to see DA rise is to work on what it tries to measure, which happens to be what helps with Google too:

1. Create content worth linking to. Practical guides, local data, case studies and clear answers to common customer questions earn links naturally.
2. Use your real relationships. Suppliers, trade bodies, accreditation schemes, local business groups and charities you support are natural sources of legitimate links.
3. Get into the news. Offer expert comment to local press and trade publications, and share genuine news about awards, projects and milestones.
4. Fix broken links to your site. If pages have moved, redirect the old addresses so any links pointing to them still count.
5. Look after technical health. A fast, secure, well-structured website makes it easier for people and search engines to use what you publish.

Our beginner's guide to backlinking covers safe link-earning in more detail, and our guide to disavowing poor quality backlinks explains when, rarely, that tool is worth using.

For most businesses, the numbers that matter are search impressions, clicks, rankings for the terms your customers use and, above all, enquiries and sales. Google Search Console shows you how Google itself sees your site, free of charge. Our guide to Google Search Console explains how to set it up and which reports to check.

Treat Domain Authority as a useful second opinion, not a scorecard. If you would like a clear view of where your website stands and what would genuinely move it forward, our team can take a look.

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