In short
Almost never. Since the Penguin update became part of the core algorithm in 2016, Google devalues spammy links automatically rather than penalising the site, and it has said repeatedly that most sites never need the disavow tool. Use it only if you have a manual action for unnatural links, or you know links were bought or built through a scheme and want to clean up before Google notices. Disavowing links because a tool labelled them toxic can remove links that were helping and does nothing for links that were already ignored.
What changed in 2016
Before the Penguin update ran in real time, spammy links could hurt a site: the algorithm demoted sites with manipulative link profiles, and site owners with a history of link-buying needed a way to renounce those links. Google released the disavow tool in 2012 for that purpose.
In September 2016 Penguin became part of the core algorithm, and its behaviour changed: instead of demoting a site for bad links, Google now discounts the bad links, treating them as if they were not there. Google's representatives have said since, many times, that the vast majority of sites have no need to disavow anything, that the tool is for sites with a manual action or a known history of link schemes, and that using it without such a reason is more likely to do harm than good.
That is the whole answer for most sites. The rest of this piece is about the exceptions and the confusion.
The two cases where disavow applies
A manual action for unnatural links. Search Console shows a manual action naming unnatural inbound links. A person at Google has reviewed the site's profile and found link schemes. The remedy is to remove what you can, disavow what you cannot, and submit a reconsideration request explaining what was done. Here the tool is essential.
A known scheme you want to clean up. The site, or a previous agency, bought links, used a private blog network, ran link exchanges, or paid for guest posts at scale, and you know it. Google may not have acted yet; disavowing the known bad links pre-emptively is prudent and is exactly what the tool was made for.
In both cases the trigger is knowledge of a scheme, not a tool's score.
The case that is not a case: "toxic" links
SEO tools assign toxicity scores to links based on the linking site's metrics. The scores identify sites that look low quality: directories, scraped content, foreign-language pages, spam blogs. Most sites accumulate hundreds of these links without doing anything, because spammers scrape and republish the web and link to everything. Google knows this and ignores those links. They are not hurting you, and disavowing them changes nothing except, occasionally, removing a real link the tool misjudged.
A toxicity report is a list of links Google is already ignoring. Acting on it is work with no upside.
Negative SEO
The fear that a competitor can point thousands of spam links at your site and damage your rankings is the most common reason people reach for the disavow tool. Google's position is that its systems are designed to prevent this, that such attacks are rare, and that they very rarely work. Cases where a site was harmed typically turn out to involve something else: a technical problem, a core update, or the site's own past link-building.
If a sudden burst of spam links coincides with a ranking drop, check everything else first, following a traffic-drop diagnosis. If nothing else explains it and the links are clearly a targeted attack, disavowing them is harmless. It is just usually unnecessary.
The risks of disavowing
The disavow file tells Google to ignore links. It does not distinguish between links that were helping and links that were not. Sites that disavow broadly, on the basis of tool scores, have removed links from small but genuine blogs, industry directories, and forums where a real person mentioned them, and have seen rankings fall as a result. Recovering from a bad disavow means editing the file and waiting for Google to recrawl every affected link, which takes months.
Disavowing also communicates something. A site that submits a large disavow file with no manual action is telling Google it believes it has a link problem. That is not itself a penalty, but it is not a signal worth sending without a reason.
If you do need to disavow
- Try removal first. Contact the linking sites; Google expects a good-faith effort before a reconsideration request.
- List domains, not URLs, where the whole site is the problem:
domain:example.com. List individual URLs only for specific pages on otherwise legitimate sites. - Be surgical. Include only links you know are part of a scheme. Do not include everything a tool flagged.
- Upload through Search Console's disavow tool, one file per property, replacing any previous file entirely; the new upload overwrites the old.
- Keep the file. It persists until replaced. Document why each entry is there.
- If there is a manual action, submit a reconsideration request describing the removals and the disavow.
- Wait. Effects appear as Google recrawls the disavowed links, over weeks to months.
The decision
No manual action and no knowledge of a scheme: do nothing, and spend the time earning links instead. A manual action or a known scheme: disavow carefully, the known links only, and request reconsideration. If a tool's toxicity report is the only evidence, it is not evidence. We cover what backlinks still do elsewhere; the short version is that the ones worth having are earned, and the ones worth disavowing are the ones somebody paid for. If you have inherited a site and are not sure which you have, book a call.
Common questions
Do bad backlinks hurt SEO?
Rarely, since 2016. Google now devalues spammy links automatically rather than penalising the site that receives them, so the scraped, foreign-language and directory links every site accumulates are simply ignored. Links can hurt when they are part of a scheme the site participated in and Google issues a manual action for unnatural links.
When should you use the Google disavow tool?
Only when Search Console shows a manual action for unnatural inbound links, or when you know links were bought or built through a scheme and want to clean up before Google acts. Google has said most sites never need it. Disavowing on the basis of a tool's toxicity score is not a reason and can remove links that were helping.
Can competitors hurt my rankings with spam links?
Google says its systems are built to ignore such links and that negative SEO attacks very rarely work. A ranking drop that coincides with a burst of spam links usually has another cause, such as a core update or a technical problem. If an attack is clearly targeted and nothing else explains a drop, disavowing the links is harmless but seldom necessary.
What happens if you disavow good links?
Google stops counting them, and rankings that depended on them can fall. Sites that disavow broadly on the strength of tool scores have removed genuine links from small blogs, directories and forums. Recovery means editing the file and waiting months for Google to recrawl each affected link.
How do I format a disavow file?
A plain text file, one entry per line, using domain:example.com to disavow every link from a site or a full URL for a single page, with comment lines starting with #. Upload it through the disavow tool in Search Console for the property; each upload replaces the previous file entirely, so keep a master copy.
