How DR is calculated
Ahrefs counts the unique domains linking to a site with at least one followed link, weights each by its own DR, and divides each linking site's influence by how many sites it links to. The result is placed on a 0 to 100 scale that Ahrefs describes as logarithmic, so moving from 20 to 30 is far easier than from 70 to 80.
Because DR is relative to every other site, it can change even when your links don't: if the web's strongest sites gain links, everyone else's score can drift.
What is a good Domain Rating?
There's no universal number. A good DR is one close to the sites that rank for the searches you care about. Compare yourself with the pages on page one for your main keywords, not with famous brands. For outreach targets, relevance and whether the post gets read matter more than DR; a modest site that ranks in your niche often beats an unrelated high-DR one. What makes a backlink high quality explains why.
DR vs Domain Authority and Authority Score
Moz calls its version Domain Authority (DA) and Semrush calls its version Authority Score. Each is calculated differently from different link indexes, so the numbers aren't interchangeable. Pick one and use it consistently. See authority score.
How to increase Domain Rating
Earn followed links from more distinct, established sites. Links from new referring domains move DR more than extra links from sites that already link to you. Buying links to raise DR is a common trap: the number may rise while the links do nothing for rankings, and paid links break Google's rules.
BacklinkGenie shows each prospect's DR next to why the post fits, and lets you set a minimum DR per site, so you can filter without letting the score make every decision. The link building cost calculator shows what different approaches cost per link.
Example
Margin starts at DR 4. After a year of earned links in relevant lists, it reaches DR 31.
Putting it into practice
Where to use it: How to choose sites to pitch and Link building cost calculator. For the longer version, read what actually makes a backlink high quality.