Last updated Jul 7, 2023
Critical Data for Keyword and Topic Research. But Can You Trust the Volume Estimates?
SEO practitioners and content writers know that keyword search volume and difficulty metrics are key inputs to finding and developing content that can rank well in organic search.
But how accurate is keyword search volume data, anyway? Can we trust what the SEO tools are predicting?
This post explores the topic of search volume accuracy, highlighting several SEO software vendors who have more to say about it, along with the pros and cons of various methods.
Read on to boost your insights into keyword search volume and accuracy considerations, plus ways to use estimated search volume data to your advantage for better SEO.
This post contains a few referral links to vendor partners. We may receive compensation for purchases made via these links, at no additional cost to buyers.
Quick Summary
- Estimated search volume for target keywords is one of the most fundamental metrics used for both PPC and SEO keyword research.
- Keyword search volume accuracy is a common concern among users of various SEO tools. Some vendors claim to have more accurate search volume data vs others.
- Google’s Keyword Planner data is usually the starting point for baseline search volume estimates.
- Smart SEOs and content writers know that even ‘zero volume’ or ‘low volume’ keywords can be good targets for content development.
- Learn more below, with insights gained from many of the top SEO keyword research tool vendors.
What is SEO Keyword Search Volume?
The Most Commonly Used Keyword Research Metric
Keyword search volume is an estimate of monthly search volume for a specific ‘keyword’ in organic or paid (PPC) search.
The term ‘keyword’ typically means a multi-word search query that a search engine user might type into Google, for example. It could also be a spoken query for voice-based search.
A keyword can be a single-word query (less likely these days), or a multi-word search query, also known as a key phrase or keyphrase. In the Google Search Console tool, it’s simply called a query.
To keep things simple, most SEO tools vendors lump all of these things together and simply use the term ‘keyword’.
Search Volume Importance for SEO
SEO pros and practitioners use monthly keyword search volume metrics to help guide their content development and writing plans.
Ideally, we want to target topic keywords that have ‘high enough’ monthly search volume to be of interest to us, while still being easy enough to rank for. This ‘easy enough’ aspect is all about the organic ‘keyword difficulty’, or KD metric. This is also calculated by most SEO tools.
See this post for much more on SEO Keyword Difficulty, also known as organic Search Difficulty (SD), and the tools that provide these insights.
The tradeoff between search volume and keyword difficulty is really important. You’ll find that many or most keywords with high monthly search volume estimates are also the hardest to rank for, as measured by KD or SD scores.
Problems with Monthly Search Volume Estimates
The various tools that provide keyword search volume estimates all have their own methods for doing this.
Some simply grab data from Google Keyword Planner (GKP) and present it pretty much as is. This is often just a wide numeric range from low to high monthly volume estimates.
Other tools incorporate what’s known as 3rd-party ‘clickstream data’ to try to triangulate on a better number within the range provided by Google.
The main problem is that the volume estimates from various tools can vary quite a bit, so it’s not always easy to know how to factor this into SEO content planning and writing tasks.
Which tool should you believe? Is the SEO software you’re already paying for giving you good keyword guidance that you can rely on? And so go these questions.
The rest of this post discusses what several of the popular SEO tools vendors have to say about keyword search volume data accuracy.
SEO software vendors discussed below include:
- SEO PowerSuite
- Mangools
- Ahrefs
- Semrush
- Moz
- Ubersuggest
- Keywords Everywhere
- Keyword Tool
Virtually all of the software vendors acknowledge that keyword search volume estimation is far from an exact science, and SEO practitioners need to understand and incorporate this into their keyword research and content planning.
(The same goes for keyword difficulty scores, by the way.)
Keyword search volume is an interesting and important topic in SEO and inbound marketing, and there is some good news in the end.
Keyword Search Volume Accuracy
SEO Software Tools Vendors and Search Volume Accuracy
This section summarizes important aspects and highlights of this issue, as revealed by several of the major SEO software makers.
Moving right along, let’s start with SEO PowerSuite.
SEO PowerSuite — Search Volume Data in Rank Tracker
I start with SEO PowerSuite because this is the set of SEO tools I use today, and they do a good job of addressing the issue of search volume estimation methods and data accuracy.
Their article on SEO tools and search volume accuracy calls search volume the ‘most deceptive metric in SEO’, and then goes on to explain why this is so.
Key points from the SEO PowerSuite article include:
- SEO tools vary widely in their estimates of keyword monthly search volumes. (This is a common observation from other vendors too. See specific examples in the article.)
- All SEO tools rely heavily on the Google Keyword Planner (GKP) data for monthly volume estimates.
- The GKP estimates are often provided only in wide ranges, with an order of magnitude difference between the low and high estimates. For example, providing only a range of 100,000 to 1,000,000 monthly search volume. That’s a 10:1 difference from high to low estimates. The same goes for ranges like 10-100, 100-1000, etc.
- Some tools pay for and use 3rd-party anonymous ‘clickstream data’ to try to refine the volume estimates to more precise estimates.
- Tools may also use the GKP Forecasts data to try to refine the estimates, but this also brings in potential error sources.
- Adjusting for the 12-month averages provided by Google can be important, especially for seasonal topics or topics that are quickly trending up or down.
- Dealing with groupings of similar keywords and close variations can be important, and different SEO tools handle this area differently.
- SEO PowerSuite’s Rank Tracker does not rely on 3rd-party clickstream data. Instead, they use GKP data and make adjustments based on one or more Google Ads volume forecast predictors. Not paying for clickstream data sources of course also helps to keep their software costs down. This helps SEO PowerSuite remain one of the value-priced SEO tool suites available.
- Alternatively, you can connect your own active Google Ads account to Rank Tracker. This avoids the wide range default GKP ‘volume buckets’ and enables much more precise search volume data straight from your Google Ads account.
- Most SEO tools are very good at predicting *relative* monthly search volumes between a set of keywords you may be considering. So, no matter what the actual provided volume numbers are, most tools do a very good job of showing relative volumes between keywords.
- If you are an active advertiser with Google Ads, be sure to leverage that data to better understand the keywords related to your core content topics. There’s a lot of analytics data available to Google PPC advertisers that can be put to good use for SEO as well.
- Also, see Google Trends to check for keyword seasonality and trending keywords and topics.
- The ‘Impressions’ data from Google Search Console may also be very helpful, once you are already ranking for a keyword (search query) of interest. See this post for more details on using Google Search Console for tracking ranking positions, impressions, and related search performance data.
- In the end, keyword search volume estimates are at best only ‘good educated guesses’ about exact monthly search volumes. Different tools use different approaches to come up with these educated guesses.
- The article also notes briefly that using organic search volume estimates to predict actual website traffic and then conversions and revenue as a result, can be tricky indeed. Also, see the Ahrefs articles below for more on this point.
If you want to further explore what SEO PowerSuite’s Rank Tracker can provide in this area (and full-blown keyword research, rank tracking, and competitor analysis more broadly), hit the banner below for a free-forever version you can download and start working with today.
Mangools — KWFinder and Search Volume Accuracy
Mangools is often considered to be a good ‘lower budget’ alternative to Ahrefs, Semrush, etc.
They provide insights into Mangools keyword volume methods and data accuracy, specifically in comparison with Google’s Keyword Planner tools.
Highlights from the Mangools article include:
- They use GKP and multiple other data sources to provide a refined volume estimate (not a wide range) that is the ‘exact average monthly search volume in the last 12 months.’
- External data sources include Moz and Majestic, which are also used for backlink data and therefore ‘keyword search difficulty’ calculations. By the way, Mangools claims to have one of the best organic keyword difficulty measures available, coupled with more exact search volume data.
Learn more about Mangools’ KWFinder here.
Mangools also does not group close variants of keywords the way GKP does. This provides a more accurate view of search volume for specific keyword variants of interest.
Ahrefs — Improving Search Volume Estimates
A highly-regarded SEO tools vendor, Ahrefs is another good source for insights into SEO keyword search volume data. They’ve done lots of interesting in-house studies based on their massive keyword database.
Some of their blog articles go into more detail on this topic.
This one reveals many of the things that most people don’t understand about keyword search volume. Lots of great examples in this article.
Several of the points made are similar to those I outlined above from the SEO PowerSuite folks, so I won’t repeat those below.
Ahrefs also makes the following helpful points worth noting:
- The Google Keyword Planner (GKP) does not provide API access to their search volume data. This makes it more challenging for all SEO tools vendors to keep their own estimates up to date. This is especially true for keywords with high volume variability.
- The annualized averages provided by Google, which are further placed into ‘volume buckets’ (wide ranges), lead to two sources of inaccuracy even within GKP itself.
- Google’s Keyword Planner is naturally designed to be more useful for advertisers, not for SEO work. This is evident when looking at GKP estimates for keyword variants, for example. (GKP can *still* be useful in some areas of SEO, as the SEO PowerSuite article notes.)
- There is often poor volume estimate consistency between Google’s own tools, such as GKP, the GKP Forecaster tool, and Google Search Console (GSC).
- Clickstream data can be highly useful when cross-referenced against GKP volume estimates. Ahrefs does buy and use clickstream data, which is in contrast to SEO PowerSuite.
- Ahrefs uses clickstream data for a number of things, including monthly volume updates, un-grouping of close keyword variants, analysis of ‘zero-click’ search results, and ‘CTR curve’ and actual organic traffic estimates for each keyword in their database.
- Ahrefs studies show that raw search volume is a poor predictor of actual website traffic. If you’re trying to predict actual CTR, conversions, and revenue just off of a search volume estimate, you may be in for a few unwelcome surprises!
- Remember that the content you’re trying to rank on Google will be in competition with any PPC advertisers and also various Google’s ‘SERP Features’ that may lead searchers to simply stay on the SERP for their answer, or click away from the ~ 10 organic search results on the page.
- The power of ranking for lots of longer-tail keywords, in addition to (or even instead of) a base keyword of primary interest, can potentially be huge. It’s much better now to think about organic content in terms of entire topic areas, not just individual keywords. Read more about keyword groupings and topic/content clusters here.
- In many cases, keywords that look unpopular (low estimated search volume) will be good targets for SEO content development. They can rank relatively quickly and bring in a surprising number of visits… well beyond what many SEO tools would have you believe. (This is, in my opinion, directly related to the ‘long-tail keyword effect’ studied by Ahrefs and others.)
- For much more on all of this, including real-world examples, read the two articles linked above and also see the Ahrefs Keyword Explorer and SERP Checker tools.
Semrush — Improved Search Volume Methods & Data
Semrush is one of the most popular all-in-one SEO and digital marketing toolkits, with product capabilities that now go well beyond SEO.
In recent years, Semrush has made significant efforts to update and improve its methods for estimating keyword search volumes.
Semrush search volume estimates now include:
- Enhanced use of 3rd-party clickstream data
- Use of new machine learning algorithms for search volume forecasting and validation
With these enhancements in place since early 2018, Semrush now claims to have the most accurate keyword search volume estimates on the market.
See the Semrush Beginner’s Guide to Keyword Search Volume for more insights.
Moz — Keyword Search Volume Accuracy Insights
As one of the best-known premium SEO toolkits, Moz needs almost no introduction. They cover all the essentials with their Moz Pro software suite.
When it comes to keyword search volume accuracy, Moz provides a number of helpful insights. In this article, Moz expert Russ Jones exposed some of the problems with using the Google Keyword Planner tool for SEO purposes.
Key points include some of the observations already noted in the SEO PowerSuite and Ahrefs pieces, so I won’t repeat them here.
Other points from the Moz article include:
- Watch out for GKP missing out on lots of good keyword recommendations. Tools like Grepwords can help fill in the missing pieces.
- Beware of GKP volume data inconsistencies with keyword spelling variations. You may find SEO opportunities worth pursuing here.
- Also, look out for strange recommendations that just make no sense for a given target topic. (This may be more important for PPC ad managers rather than SEO folks.)
- Moz, like Ahrefs, uses 3rd-party clickstream data and proprietary methods to refine its keyword volume estimates. They claim to have about 95% accuracy/consistency with Google Ads volume estimates. See their Keyword Explorer tool to learn more about their capabilities.
Looking at Relative Keyword Search Volumes
Russ also provided this study on Keyword Volume Relational Accuracy, which includes a statistical R-Squared value for a data set tested with Semrush, Ahrefs, and Moz.
Guess who wins here? You’ll have to read the short article to find out.
This study is more about predicting relative volume for various keywords, and not on actual numeric accuracy of search volume estimates. It uses Google Trends data as a measuring stick against which to test the three SEO vendors.
For practical SEO applications, this issue of relative search volume is most important when you need to choose between Keyword 1 and Keyword 2 (or even more keywords) when deciding how to focus a piece of new content.
Other Keyword Volume Research Tools
Ubersuggest
Ubersuggest doesn’t go into much detail at all about its search volume accuracy. They address it simply in their FAQ, as shown below.
My best guess is that Ubersuggest uses Google Keyword Planner data as-is, perhaps from 3rd-party sources. They also provide monthly volume data from GKP. This is helpful in many cases, and not all SEO tools do this.
Keywords Everywhere
Keywords Everywhere is a paid keyword research tool that claims to have great volume data accuracy.
Keyword Tool
Keyword Tool goes a bit further, claiming to be 100% accurate and exactly in line with what you would get from the Google Ads Keyword Planner.
Lots of Tools and Keyword Search Volume Accuracy Claims
These are just a few examples of a wide range of SEO keyword research tools on the market today.
Most of them claim to be ‘accurate’, but only a handful of vendors, like those profiled in more depth further above, go into helpful detail about their volume estimation methods, strengths, and accuracy limitations.
Related Keyword Research Techniques
Google Autocomplete / Autosuggest
For a non-quantitative but still useful keyword research technique, look at what search queries Google automatically suggests for you as you type in various keywords or key phrases.
See the example below.
Any search suggestions that show up here, in addition to the ‘seed keyword’ you type in, are likely to be active search queries from Google’s huge user base. In other words, there is non-zero true monthly search volume for these terms.
If your favorite keyword research tool shows zero or maybe only 1-10 searches per month for a potential target keyword, try using this technique to see if your term pops up as an autosuggest or autocomplete idea from Google.
If it does, you may want to factor this positive volume indicator into your keyword targeting decisions.
SEO Keyword Tools and Google Autocomplete
Keyword research tools will often automate this process by scraping Google’s autocomplete suggestions and then assigning monthly volume estimates and other keyword metrics (including search difficulty) to them.
Here’s where that is available in SEO PowerSuite’s Rank Tracker program. It’s one of nine main methods within their overall Keyword Research module.
In Rank Tracker’s autocomplete tool, you can choose your target search engine and language, set negative keywords for the tool to omit (optional), and then seed the tool with your base keyword(s).
Then hit the green Search button and see what results come in!
Search Volume and the Keyword Golden Ratio Technique
This technique, also called the KGR technique or method, was first popularized and promoted by Doug Cunnington.
See this Mangools article for a great intro to the KGR technique, with examples.
You’ll also learn how to use tools like Mangools KWFinder to help partially automate the process.
As with any ratio metric, there’s a numerator and a denominator in the KGR.
Numerator = the number of ‘allintitle’ search results for a target key phrase.
Denominator = the estimated monthly search volume for the key phrase.
For KGR and keyword selection purposes, Doug likes to cap this at 250 estimated searches per month. See the Mangools article for more rationale behind this.
KGR: Web Content Supply vs Searcher Demand
We can also think of the KGR as a supply vs demand type of analysis. The number of allintitle search results represents the supply of articles that are squarely focused on the search topic. The monthly search volume represents the demand side from Google searchers.
If the supply side is low but the demand is relatively high, then there’s potentially a great opportunity to rank some quality new content for that keyword phrase.
Note: Allintitle is an advanced Google search operator that limits results to only those web pages or posts that have ALL of the search terms in the HTML Title tag.
If the resulting KGR is less than 0.25, it may be a great target keyword for easier ranking.
If KGR is 0.25 to 1.00, it *may* still be a decent target key phrase.
For KGR > 1.00, the key phrase is bad since the supply of existing well-targeted web content is too great, and/or the estimated monthly search volume is just too low.
Keyword Golden Ratio and Long-Tail Keywords
The KGR method, with its monthly volume restriction (< 250 searches/month) and tight target ratio (< 0.25) for finding winners, will generally favor long-tail and even ultra-long-tail keywords.
You’ll probably be working with ~ 4 or more words in the best KGR keyphrases.
Modified KGR Method
I’ve tried the KGR technique on a couple of topics and can confirm that it works to rank content faster, sometimes almost immediately on Google Page 1.
Nowadays, even if I don’t do the full KGR analysis on a target keyword, I at least check the Google Allintitle and Allinurl results to see how many results show up.
If the number of search results returned is quite low or at least < 100, I know I might have a good target keyword for some great fresh content with faster ranking potential.
Anyway, when you’re doing keyword volume research and seeing low monthly volumes for some interesting search queries, think about using the Keyword Golden Ratio technique as well.
You may come up with some great content ideas that can rank faster than usual.
Keyword Search Volume Accuracy — Final Thoughts
Working with Imperfect Keyword Search Volume Data
At this point, we know that SEO keyword research is an imperfect science, at best.
All of the many SEO tools vendors are hampered by the same limitations of using Google’s Keyword Planner estimates. At least a few of them — including SEO PowerSuite, Ahrefs, Semrush, Moz, and Mangools — apply further refinements to the basic GKP estimates, and they offer helpful details about the strengths and weaknesses of their approaches.
For knowledgeable SEO practitioners, some of these keyword volume uncertainties can also be used for competitive advantage.
For example, working with long-tail keywords and narrower topic niches that competitors may ignore due to incorrect ‘zero volume’ perceptions.
Or manually checking Google Autocomplete, Google Search Console, and Google Trends for signs of positive search volume even when the SEO tools indicate no or very low volume for a specific key phrase.
Or using the Keyword Golden Ratio technique and mindset to cover a topic from multiple interrelated angles, picking up quicker ranking victories and valuable website traffic along the way.
Good luck with your keyword research, topic planning, and other SEO work. Feel free to add your own insights below with any thoughts, feedback, or related questions.
After reading this, I’ve realized that SEO is all about keywords and nothing else. Indeed, keywords are all that end up mattering.
Hi Greg – Thanks for reading and adding your thoughts.
Keywords (and search volumes) are certainly very important, but there are many other important aspects to SEO as well. Don’t forget your overall topic/content structure, content and site quality, and other factors that impact your organic visibility.
So keywords… yes… but just not to the exclusion of other SEO considerations. Good luck!
very interesting article. very sensitive topic. I think it’s good to have more keyword suggestion tools. But for search volume you need to have only one because every tool has inaccuracy and you need to minimize that. Therefore, it is nonsense to compare word searches between different tools.
Then there’s another thing… some tools only list searches for desktop, others for both desktop and mobile. And almost no one addresses that, but I think it’s important.
When I watch it for a long time, I only trust SEO Power Suite and Ahrefs. But I would like to have just one.