[CRITICAL UPDATE] Which Is The Best Backlink Checker? - The Million Domain Case Study (2024)

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To find out which is the best backlink checker, I devised a real test.

I decided to:

To see who really is the best quality backlink checker once and for all.

Because I’m sure you’ve seen all the other studies that use either 4 domains, 100 domains or 1,000 domains to compare database sizes.

So I decided to cut to the chase with a sample size of 1 million domains.

And the results are in…

Introducing You To 4 Backlink Checkers You Can Use

1. Ahrefs

Ahrefs has spent years as the KING of backlink checkers. They’ve won all of my testing historically.

But this time round they were up against some fierce competition especially after SEMRush raised $40 million to expand last year.

Check out my Ahrefs vs Semrush blog to see which tool performs the best overall.

2. SEMRush

SEMRush has always played second fiddle to Ahrefs.

Because they’ve always aimed to be a complete SEO digital marketing tool, some of their specific backlinking tools – like their backlink checker, backlink explorer or backlink monitoring tool- 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.

See how Semrush stands against one of its biggest competitors: SEO Powersuite in my SEO Powersuite vs Semrush comparison.

3. Majestic

Majestic is a seasoned veteran that makes some big claims about the size of their link database (even though we have proven it not to be true time and time again).

Can their backlink tool match their sales pitch this time?

History says no.

4. SEO Spyglass

SEO Spyglass started life as an ultra-slow desktop SEO Tool. Never much of contender.

But now they are back with a RAPID upgrade and new database. Is it enough?

Let’s take a look…

4x Million Data Points: How The Backlink Checkers Were Tested

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 domains based on their number of referring IPs and Subnets according to Majestic.

As such:

1. Each of these domains should have a TON of data
2. Each of these domains 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:

These are more reliable than counting a vague “link”. (More on that here.)

That gave me 4x million rows of backlink data – Yay! – to work with.

You can download all of that data right here.

Here Is How I Collected This Data

I got in touch with a number of backlink analyzer 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.

Which Backlink Checker On The Market Is The Best?

So after crunching all of the information from each SEO backlink tool…

…a clear winner emerged-

Results – Total Wins By IP – Ahrefs

Results – Total Wins By Subnet – Ahrefs

And The Best Backlink Checker Award Goes To…

The greatest SEO backlink checker that money can buy right now is Ahrefs.

They have-

And not to mention it’s the tool I use every single day to complete a range of SEO tasks and analysis.

Ahrefs have rightly earned their place as the greatest backlink checker on the market right now (and best SEO tool in my opinion).

But:

It’s important you keep on reading because there are some flaws and other things to consider when looking at backlink checkers.

There Were A Few Potential Flaws With This Experiment

I’ll be the first to admit…

My methodology for this backlink test and analysis 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 backlink tools look at the same site. They each report:

SEMRush would receive the “point” for their “win”. That is added to their tally. Wash, rinse and repeat for each of the tests.

So the test only represents the number of times each backlink tool beat its opponents.

And the results are showing us that it is unlikely for other backlink checker tools to have more data than the Ahrefs tool 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 domain 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 backlink 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 has 3 different databases, Majestic have 2 and SEMRush has 1 which are all defined differently-

• Ahrefs
• 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
• Majestic
• Fresh = All links that were seen as live during the past 3 months
• Historic = All links ever seen in history
• SEMRush
• 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-

Which still isn’t really fair!

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 information we didn’t see that either because the IP & Subnet information 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 When It Comes To Backlink Checkers Size Isn’t Everything!

The “size of the database” has been the defining point of “top backlink checkers” 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 presentation of that data does not connect to the goal of increasing your search traffic.

And depending what questions you’re asking, might mean what is the right backlink checker for me – isn’t the right backlink checker for you and won’t be as helpful with your traffic.

Why Ahrefs Is Great And My Recommended Tool

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 SEO 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 or report you need quickly. Whether that’s anchor text or the best backlinks.

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 complete 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 right backlink checker if you’re facing a manual link penalty.

Why SEMRush Is Great

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 for analysis.

See for yourself:

But:

If you want a budget friendly tool with highly customizable reporting, you might want to check out SEO Spyglass or my Semrush alternatives blog post.

Why SEO Spyglass Is Great

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-

No other tool can compare with it’s customization & advanced reporting features.

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 correct 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 For These Backlink Checker Tools

You also need to pay close attention to the overall cost of ownership of each tool because this can get really expensive quickly if you are not actively using them-

• Ahrefs starts at $99/mo
• SEMRush starts at $99.95/mo
• Majestic starts at $49.99/mo

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 backlink checker is 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 results report 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 top backlink checker on the market right now is Ahrefs. Based on my testing Ahrefs have the biggest database of links and the most usable, quality data! But they are also the most expensive tool which might not make them the best backlink tool for you.

So, if you’re on a budget, you should read my free seo tools list.

Thanks to all of the backlink checking competitors that took part in the test!

I look forward to doing a complete analysis of these tools again in the future, but for now – the links have spoken.

If you want to test some more backlink checker tools, take a look at Sitechecker who specialise in backlink tracking.

Which is the backlink checker for you? Let me know in the comments…

Further Reading On Backlink Checkers

• 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