CRITICAL UPDATE: This case study was originally published on September 10th 2019 but there was an conflict with how SEMRush choose to count IP data which led to them being falsely declared the winner. SEMRush have provided an updated dataset & I’ve updated the case study as of the 23rd September 2019.
To find out which is the best backlink checker, I devised a real test.
I decided to:
- Take the 4x best backlink checkers on the market
- Use them to collect data for the same 1x million links
So I decided to cut to the chase with a sample size of 1 million domains.
And the results are in…
What Will I Learn?
Introducing The Competitors
But this time round they were up against some fierce competition especially after SEMRush raised $40 million to expand last year.
SEMRush has always played second fiddle to Ahrefs.
Because they’ve always aimed to be a complete digital marketing tool, some of their specific SEO tools – like their backlink checker – have just never been as good.
They invested a lot of resources and added some exceptional new features.
Plus… they’ve really being bragging about their upgraded backlink database recently.
Can their tool match their sales pitch?
History says no.
4. SEO Spyglass
But now they are back with a RAPID upgrade and new database. Is it enough?
Let’s take a look…
Before I reveal the winner I want to talk you through this test’s methodology.
The domains for this test were pulled from the Majestic Million as I’ve always done.
These are the top 1x million websites based on their number of referring IPs and Subnets according to Majestic.
- Each of these sites should have a TON of data
- Each of these sites should have consistent numbers across all 4x tools
The 1x million domains were run through each the 4x tools. I then looked at which tool showed:
- The most referring IPs
- The most referring Subnets
That gave me 4x million rows of data – Yay! – to work with.
You can download all of that data right here.
How Was This Data Collected?
I got in touch with a number of backlink checker tools and asked if they wanted to take part in the testing.
I had a phone call with each tool to discuss the test and each tool supplied their own data set to be used in the comparison.
The IP & subnet numbers provided were then manually verified against their user interfaces and then sent to an independent 3rd party to create this analysis.
So after crunching all of the data from each tool…
…a clear winner emerged-
Total Wins By IP – Ahrefs
Total Wins By Subnet – Ahrefs
The best backlink checker that money can buy right now is Ahrefs.
- The biggest backlink database
- The most usable data (more on that below)
Ahrefs have rightly earned their place as the best backlink checker on the market right now (and best overall SEO tool in my opinion).
It’s important you keep on reading because there are some flaws and other things to consider when looking at backlink checkers.
A Few Potential Flaws With This Experiment
I’ll be the first to admit…
My methodology for this test is far from perfect. So I wanted to highlight some of the potential flaws.
Flaw #1: Wins vs Absolute Numbers
It’s important to note that the graphs show the number of “wins” and not absolute numbers. Let me explain…
Let’s say all 5x tools look at the same site. They each report:
- Ahrefs: 100 referring IPs
- SEMrush: 101 referring IPs
- Majestic: 99 referring IPs
- SEO Spyglass: 100 referring IPs
So the test only represents the number of times each tool beat its opponents.
And the data is showing us that it is unlikely for other backlink checkers to have more data than Ahrefs does.
Flaw #2 – Each Tool Picks Up Different Links
Each tool has its own index. That’s 4x unique databases.
Not all databases share the same links. What appears in Ahrefs may not in SEMRush.
Let me offer an example.
If Ahrefs and Majestic are comparing the same site they may find the same number of links. But these links may not be from the same sources:
See what I mean?
If you wanted a full picture you would need to buy all 4x tools and cross-reference.
(I don’t recommend you do this. Keep it simple.)
Flaw #3 – Not All Backlink Databases Are Equal
Every tool takes a different approach to how they find, store and count data which means you are not always making an Apples to Apples comparison.
For example Ahrefs have 3 different databases, Majestic have 2 and SEMRush has 1 which are all defined differently-
- Live – All links that are currently live
- Recent – All links in the live index PLUS all lost links in the past 3 months
- Historical – All links ever seen in history
- Fresh = All links that were seen as live during the past 3 months
- Historic = All links ever seen in history
- Fresh = All links crawled & live in the last 6 months
As you can see there are huge differences in how those datasets are defined.
Ahrefs and Majestic both offer a 3 month database which makes comparison easy, but SEMRush only offers a single database of 6 months.
And because SEMRush do not offer a historic database, the closest to a “fair” test we could get was to compare-
- Ahrefs Recent (3 months)
- Majestic Fresh (3 months)
- SEMRush Fresh (6 months)
On top of that problem is the fact that tools count data differently.
You see most backlink checkers only count the most recent IP they found for a domain meaning that 1 domain = 1 IP.
But SEMRush records every IP they have found for a domain in the last 6 months which can mean that 1 domain = 30 IP’s.
That is because they count the data differently than any other backlink checker.
And because we didn’t collect referring domain data we didn’t see that either because the IP & Subnet data SEMRush provided did check out 100%!
But the way they count all IP’s found for a domain in the last 6 months, led to inflated IP and Subnet counts. That was corrected with an updated dataset from SEMRush on September 19th 2019 to allows us to make a fair comparison.
But Size Isn’t Everything!
The “size of the database” has been the defining point of the “best backlink checker” for years and its a claim that is widely used across the marketing material of many tools.
People always think that bigger is better, but as the old saying goes:
It’s not how big it is, it’s how you use it.
The point of buying any SEO tool is to increase your search traffic right?
So it really doesn’t matter how the big the database is, if the presenation of that data does not connect to the goal of increasing your search traffic.
And depending what questions you’re asking of the data, might mean what is the best backlink checker for me – isn’t the best backlink checker for you.
Ahrefs is my go to tool and has my favourite interface, for example.
It’s pretty intuitive and doesn’t take a lot of time to get used to. You can run searches and retrieve old data. It’s all there in the dashboard waiting for you and it’s rapid fast!
They provide you with a lot of 1x click filters to help you find the information you need quickly. For example, you can filter by link type…
Or by platform:
They also generate lots of handy reports, like their best by links report:
Or their best by links’ growth one:
Which you just can’t do in any other tool, no matter how big their database is.
But you can’t import links from other tools into Ahrefs which doesn’t make it the best backlink checker if your facing a manual link penalty.
SEMRush has an easy to understand dashboard as well-
But it also has fewer filters and the ones they do have are not always useful.
See for yourself:
If you want a budget friendly tool with highly customizable reporting, you might want to check out SEO Spyglass.
And if you haven’t checked it out for a while I suggest you do because they had a huge update recently which totally transformed the user friendliness-
A lot of people like the overhauled version because it is-
- Super customisable
- Rapid fast
You can also import backlink data from third-party tools like Google Search Console, Ahrefs and SEMRush to get complete coverage of your link profile.
And those are both things that you can’t do that in any other tool!
So take some time to play around to find which is the best backlink checker for you.
Because it really depends on what questions you are asking of the data.
But for me personally:
Ahrefs has the biggest database and THEY KNOW how to use it!
The Cost of Ownership
You also need to pay close attention to the overall cost of ownership of each tool because this can get really expensive really quickly if you are not actively using them-
SEO Spyglass is a $124.75 one time fee for the first year. Then it’s only $4.17/month after that.
The cost of ownership couldn’t be any further apart and that might be a defining point of deciding which is the best backlink checker for you.
Because after 12 months of owning Ahrefs, it would have cost you nearly $1,200 versus a cost of $124.75 to own SEO Spyglass.
After 3 years that is the difference between $3,600 and $224.83 so don’t overlook the cost of ownership when deciding which is the right backlink checker for you.
Wrapping It Up
The results of the 1x million domain backlink checker test are in:
No other test has used a dataset this large to compare backlink checkers ever!
But after reviewing the data and spending time using each of the tools, I can say with absolute confidence that-
Which Is The Best Backlink Checker?
If we had to crown one winner, the best backlink checker on the market right now is Ahrefs. Based on my testing they have the biggest database and the most usable data! But they are also the most expensive which might not make them the best for you.
Thanks to all of the backlink checking tools that took part in the test!
I look forward to repeating the test again in the future, but for now – the data has spoken.
Which is the best backlink checker for you? Let me know in the comments…
- Russ Jones’s discovery that called for a recount in this test
- Majestics post about comparing backlink checkers
- Brian Dean’s test (4 domains + functionality)
- SEMRush’s test (100 domains)
- Russ Jones’s test (1,000 domains)
- Previous Ahrefs vs Majestic test
- A look at the freshness of various backlink checkers data