How to Check Backlink Quality (5 Free Checks, In Order)

A backlink is worth something if the domain giving it is itself referenced by other people, an editor chose to place it, the subject is related, it is not marked sponsored, ugc or nofollow, and the page still exists with the link still on it. Those five checks, in that order, are all free. The first four can be answered by software. The second one, whether a human chose to place the link, cannot, and it is the one that decides most cases. In the Revised directory, as of 14 September 2026, 11,254 of 11,255 listings (99%) have at least one referring source named, which is what makes check two possible before you buy anything.

Work them in order and stop at the first failure. Most links fail check one.

Check 1: is the linking domain referenced by anyone?

A link is a vote from a domain, and a domain with no votes of its own has nothing to pass. This is the check that eliminates the most links the fastest.

Run the linking domain through a backlink tool and look at its referring-domain count, not its authority score. A site with three referring domains is a site nobody references, whatever its score reads. Our backlink checker is free and names the notable referring sources rather than only counting them, and checking backlinks for free covers the other free methods.

Google's ranking systems guide is the reason this works at all:

We have various systems that understand how pages link to each other as a way to determine what pages are about and which might be most helpful in response to a query. Among these is PageRank, one of our core ranking systems used when Google first launched.

Software answers this one completely.

Check 2: did an editor choose to place it, or did somebody place it themselves?

This is the check that matters most and the only one a tool cannot do for you. Open the page and read it.

A link inside an article's body, in a sentence where the link is the reference the sentence needs, was placed by a writer. A link in a comment, a forum signature, a resource-page submission, a profile field or a footer widget was placed by whoever wanted it. Both are links. Only the first one is evidence of anything.

Google's link spam policy is a list of the second kind. It defines link spam as "the practice of creating links to or from a site primarily for the purpose of manipulating search rankings" and enumerates the patterns, including:

Excessive link exchanges ("Link to me and I'll link to you") or partner pages exclusively for the sake of cross-linking

Low-quality directory or bookmark site links

Keyword-rich, hidden, or low-quality links embedded in widgets that are distributed across various sites

Widely distributed links in the footers or templates of various sites

Forum comments with optimized links in the post or signature

Read the anchor text while you are there. An exact-match commercial phrase in the middle of unrelated prose is a placed link that somebody wrote the sentence around. Google's policy names that too, under advertorials: "links with optimized anchor text in articles, guest posts, or press releases distributed on other sites".

Check 3: is the subject related?

A link from a page about your subject is worth more than a link from a page about nothing in particular, and both are worth more than a link from a page about something unrelated.

The test is not whether the two sites share a category label. It is whether a reader on that page would plausibly click through. A gardening blog linking a tax-software page did not do it because its readers wanted tax software.

This check also carries the whole argument about buying old domains. The references an expired domain holds were about a subject, and they only help a site in that subject. Evaluating an expired domain's link history works through that in detail.

Check 4: what does the rel attribute say?

Open the page source and look at the link tag. Google's documentation on qualifying outbound links defines three values:

And on all three together:

Links marked with these rel attributes will generally not be followed.

"Generally" is doing work in that sentence and nobody outside Google knows how much. Treat a qualified link as worth traffic and brand exposure, and worth close to nothing for ranking. Dofollow vs nofollow links has the longer version.

Software answers this one, and browser extensions do it at a glance.

Check 5: is the page still live, and is the link still on it?

Link data goes stale in both directions. A tool can list a link that was removed a year ago, and the page holding it can be gone entirely.

Fetch the URL and search the response for your domain. A 404, a redirect to a homepage, or a 200 with no link is a link you do not have. This is the check people skip, and it is why two tools report different counts for the same site: they last crawled the page at different times.

For an old domain the decay is the point rather than an error. Pages get deleted and sites get redesigned, so a domain that has been dead for years is losing references quietly the whole time.

Which checks can a tool answer?

Four of five are automatable. The one that is not is the one that decides whether the other four were worth running.

What disqualifies a link outright?

• The linking domain exists to host links, with no audience and no traffic of its own
• The link is in a footer, sidebar or widget replicated across many sites
• Anchor text is an exact commercial phrase in prose that was written to hold it
• The page is a list of unrelated outbound links with no editorial thread
• The site's outbound links are in several languages and several unrelated subjects
• Someone sold you the link

A profile of mostly these is the shape toxic backlinks and the disavow tool covers, including the case for doing nothing about them.

Using the Revised directory for this

Every listing carries the output of checks one, three and five before you reveal the name. Practically:

1. Open the directory. In Quality, set Referring domains to the band you want and Spam signal to the low band. As of 14 September 2026, 9,552 of 11,255 listings (84%) passed that screen.
2. Read the Linked by column, which is check two in list form. Start from a source hub if you want one kind of reference only: domains with .edu backlinks held 108 listings, .gov backlinks 42, and Wikipedia backlinks 4,772.
3. Set Category in Basics to your subject, which is check three.
4. In History, set Checked to a recent window. Every listing in the directory had its availability re-checked within 30 days.
5. Run a domain you already own through the backlink checker and the domain authority checker to get the same view of your own profile.

Filtering and sorting are free. A plan buys reveals, so run the checks on the shortlist first.

FAQ

How do I know if a backlink is good? Five checks: the linking domain is referenced by others, an editor placed the link, the subject is related, it is not marked sponsored, ugc or nofollow, and the page is still live with the link on it.

What makes a backlink low quality? Being placed by whoever wanted it rather than by an editor. Footer and widget links, forum signatures, submitted directory entries and paid placements are all in Google's own list of link spam examples.

Do nofollow links have any value? Traffic and exposure, yes. Ranking credit, mostly not. Google says links marked with these attributes "will generally not be followed".

Can I check backlink quality for free? Four of the five checks, yes. Tools report the linking domain's own references, the rel value and whether the link is still live. Whether an editor chose to place it needs you to open the page.

How many backlinks do I need? Fewer good ones than the number people quote. Read the referring-domain counts of the pages currently ranking for your term instead of aiming at a number.

Does a high authority score mean the link is good? No. A score is one vendor's summary of a domain's inbound links and says nothing about whether this particular link was editorial, related or still live.

If you would rather start from links that already passed these checks, browse the Revised directory of expired domains with backlinks. Every row names the sources that reference it, shows its referring-domain band and its spam screen, and records when availability was last verified, all before the name is revealed.