Domain Authority (DA) – Moz

Domain Authority by Moz is a rating, between 1 and 100, of a predicted ability on how a website will rank. It is a domain-wide metric and is mainly calculated through the amount of backlinks a website has. The DA of a website is relative to a group of websites – for example, Facebook, Google, Pinterest etc will have DA of 100 and these are the root domains. The idea is that each and every website on the internet is then compared to these “root domains” and a score is calculated in comparison to the root domains. This is why a website may experience random drops in DA – it’s not necessarily because the website has suddenly acquired bad links, but it can be because a root domain has suddenly acquired a lot more links which will impact the comparison. DA is calculated on a logarithmic scale, meaning the higher your DA gets, the harder it will be to grow it even more.

Domain Rating (DR) – Ahrefs

Domain Rating by Ahrefs serves the exact same purpose as Domain Authority by Moz and is rated between 0 and 100 – but they are calculated differently. Domain Rating is calculated exclusively by the backlink profile of the website and places a much greater influence on the unique referring domains the website has and how much the link equity (or link juice) is spread across the outbound links, whereas Domain Authority places more influence on total backlinks, even if they’re from the same domain, and does not calculator link equity. Domain Rating is also calculated on a logarithmic scale, so the higher a website’s DR, the harder it will be grow it more.

Page Authority (PA) – Moz

Page Authority by Moz is the exact same as their Domain Authority, but it only looks at the specific page to calculator a score and ignores the rest of the domain. It is widely seen as a good replacement for Google’s previous public ranking of Page Rank – but PA and PR are calculated completely differently so this is just a bad practice. PA is calculated using a logarithmic scale.

URL Rating (UR) – Ahrefs

URL Rating by Ahrefs is similar to the Page Authority metric by Ahrefs. The key difference between the two is that URL Rating takes into account internal links and includes a dampening factor. This is where an algorithm calculates the importance of a page based on how many clicks away it is from the homepage, or other important landing pages. UR is the closest thing to Google’s Page Rank that any mainstream SEO tool has created as UR and PR are calculated using very similar factors. UR is calculated using a logarithmic scale.

Trust Flow (TF) – Majestic

Trust Flow by Majestic is rated between 0 and 100 and is a metric to calculate the trustworthiness of a website. Similar to Moz’s DA, Trust Flow is calculated using a set of root domains. Websites that are closely linked to root domains will have a high trust flow, whereas websites that have links from questionable websites will have a low trust flow. Trust Flow can be used as a domain-wide metric as well as page-level metric.

Citation Flow (CF) – Majestic

Citation Flow by Majestic is rated between 0 and 100 and is a metric to calculate how influential a backlink from the website or page would be. It is the only metric by a mainstream SEO tool that actually attempts to calculate the link equity (or link juice) that a website or page can provide. 

Trust Ratio – Majestic

Trust Ratio is the ratio of a website or page’s Trust Flow and Citation Flow (calculation: TF/CF=Ratio) The perfect score would be 1 – the closer to 1.00, the better the link. If the ratio is considerably lower than 1 then the website has a lot of link equity, but this is being passed from untrustworthy websites. If the ratio is considerably higher than 1 then the website is linked from a lot of trustworthy websites, but not a lot of link equity ie their links are from trusted websites but on unimportant pages. Therefore, being closer to 1.00 represents a balance of link equity and trust.

Topical Trust Flow (TTF) – Majestic

Topical Trust Flow is a categorisation of a website depending on the backlink profile of the domain. This is a great metric to use to determine the relevancy of the backlinks a website has and shows how Google might categorise a website based on the anchor texts and topics of backlinking websites etc. It shows how Google can understand a website by looking at backlinks beyond something as simple as the anchor text.

Referring Domains (RD) – Global

Referring Domains is a global metric across all tools and is calculated in the same way. If a domain links back to the website, no matter how many individual backlinks come from that domain, then it is counted as a single Referring Domain. RD is useful once you consider the law of diminishing returns for backlinks: essentially, multiple backlinks from the same domain will never be as impactful as the first link so there is no advantage in building many backlinks from a single domain.