What are backlinks, and which ones count?

The four parts of a link

Every link is a short piece of HTML on someone else's page. Four things about it decide what it is worth.

Google's documentation on crawlable links sets out the mechanics. Google can follow a link written as an a element with an href attribute. A link added by JavaScript counts if it ends up in the page as that same markup; a button that changes the page with a script, and has no href, does not.

The same page asks for anchor text that is "descriptive, reasonably concise, and relevant" to the page linked to, and names "click here" as the thing to avoid. For a link on an image, the image's alt text does the job of anchor text.

Links marked not to count

A site can tell search engines how to treat a link with the rel attribute. Google's guidance names three values:

Until 2019 Google ignored nofollow links entirely. On 10 September 2019 it announced that all three values would be treated as hints: Google may take them into account or not. They became hints for ranking that day, and for crawling and indexing on 1 March 2020. A link with none of these values is what people call a "dofollow" link, though there is no such attribute. It is simply a normal link.

How often sites mark their links

We wanted to know whether marked links are the exception or the rule, so on 14 November 2026 we read the home pages of the same 60 large sites as our robots.txt study and counted every link that pointed to another website.

Thirty-four home pages could be read and had outbound links on them. Between them they had 702 outbound links, and 96 of those (14%) carried nofollow, sponsored or ugc. Almost all were nofollow; one link was marked sponsored and one ugc.

The marking was concentrated in a few places. The Verge marked 56 of its 77 outbound links, TechCrunch 8 of 9 and Healthline 9 of 18. DigitalOcean marked all 10 of its own. Twenty-eight of the 34 sites marked none at all, including Stripe, HubSpot, Salesforce, GitHub and Wikipedia.

Read that with its limits. A home page links out mostly to social profiles and app stores, not to the editorial links that matter for search, and 26 of the 60 sites either refused our request or had no outbound links on the page. It is a check of 34 home pages on one day, and the data is published so you can see every site. What it does show is that "most links on the web are nofollow" is not true of large sites' home pages.

Types of backlinks

The prices come from a test Ahrefs describes in an article last updated in July 2024. It pitched 180 sites for paid guest posts and contacted 450 sites across nine niches to buy links in existing articles; 12.6% of the second group agreed to sell. The same article cites a survey of 755 link builders by Authority Hacker that put the average paid link at $83. The test itself is undated, so treat the figures as a guide to the order of magnitude.

What makes a link worth having

Google does not publish a formula. Its spam policies say what does not count: links made to manipulate ranking. What follows is our reading of what a link that does count tends to have, not a rule from Google.

• The linking page is about the same subject. A link from a cycling blog to a bike shop means something. A link from a casino page does not.
• Real people read the linking page. A page that ranks and gets visitors passes on more than one nobody visits.
• It sits in the body of the text. A link inside a sentence that refers to you beats one in a footer or a list of "partners".
• Somebody chose to put it there. The link exists because the writer thought their reader would want your page.

Backlinks and referring domains

Ten links from one website are ten backlinks and one referring domain. The second number is the one to watch. A hundred links from a single site that links to you in its footer is one vote, repeated a hundred times.

Most backlink tools report both. If yours shows thousands of backlinks from a few dozen domains, look at which domains: a single site-wide footer link inflates the first number and changes nothing else.

How many backlinks do you need?

There is no number. What you need is to be in the same range as the pages already ranking for the search you care about, and that is something you can measure:

1. Search the phrase you want to rank for and note the ten pages on the first page.
2. Look up the referring domains for each of those pages, not for their whole sites, in a backlink tool. Ahrefs has a free backlink checker; the paid tools show more.
3. Take the middle value of the ten. That is roughly the bar.
4. Compare it with your own page's count. If you are far below, links are a likely part of the gap. If you are close and still not ranking, the gap is more likely the page itself.

For step 4, the page comparison tool puts your page and a competitor's side by side on 12 on-page checks, which rules out the simpler causes first.

How to see your own

Google Search Console has a free Links report that lists the sites linking to you and the pages they link to. It is a sample, not a complete list, and it shows only your own site. To see a competitor's links you need a third-party tool.

How to get them

Slowly, and mostly by being worth linking to.

• Publish something another writer can cite. A number you measured, a tool, a clear explanation of something confusing. People link to things they can use. We built free tools and ran two small studies partly for this reason.
• Get onto the pages that already list businesses like yours. Comparison articles, your trade's directories, review sites. Email the author with one specific reason you belong there.
• Be a source. Answer questions in your field under your own name, in forums and for journalists. The link follows the usefulness.
• Turn partnerships into links. Suppliers, integration partners and associations you belong to often have a page that lists members. Ask to be on it.

Should you buy backlinks?

Google's spam policies say buying or selling links that pass ranking is link spam. The same policy says a paid link is fine when it is marked rel="sponsored" or rel="nofollow", because then it does not pass ranking. So a paid link that is properly marked is an advertisement: worth buying for the visitors it sends, and for nothing else.

In practice, most sites that sell links do not mark them, because a marked link is not what the buyer wants. That is the risk. Google's most likely response to links it does not trust is to ignore them; the worst is a manual action against a site that relied on them heavily.

What to avoid

The same spam policies list excessive link exchanges, automated programs that create links to your site, and links in widely distributed templates or footers. The practical test for any offer is whether you would be comfortable with a customer seeing the page the link sits on. Our guide to link exchanges covers swaps in detail, including the rules we enforce in our own.

Do backlinks matter for AI answers?

In a different way. An assistant builds its answer from pages it finds through search, so a page that ranks is a page that can be read and cited, and links help it rank. Beyond that, what gets a business named is being mentioned on the pages the assistant reads, with or without a link. The steps are here.