Google keyword planner is an awesome, free tool that pretty much anyone can use. As long as you have an AdWords account, you have access to keyword planner. Your account doesn’t even need active ads to use this tool, so there’s really no reason not to use it. But for as great as keyword planner is, it’s also confusing as all get up when you are looking for search volume.
That Keyword Receives How Many Searches?
Go to Google keyword planner and type a single keyword that you’d like to rank for. Is there a huge discrepancy between the lowest amount of searches and the highest? You’ll notice below that we searched for the monthly volume of “SEO.” You’ll also notice that the average searches can fall anywhere between 100,000 and 1,000,000. How is that even possible? The monthly search volume can’t possibly fluctuate that much month to month, can it? The answer is no.

So what’s happening here and why does the search volume offer drastically different answers? To give you a better understanding of that, Russ Jones from Moz offers us some insight:
Google’s Data is ‘Combined’: Google Keyword Planner (GKP) combines related words together in their Keyword Planner volume estimates. For example, the keywords ‘seo’ and ‘search engine optimization’ are combined into a single volume in GKP. This gives the illusion that both keywords are searched a hundred thousand times, when in reality, the number GKP gives is the cumulative value. This can often include many close variants of the keyword. Google does this because if you were to advertise on the term SEO, you would show up for search engine optimization as well. Google is giving you a number relative to how things would occur in Adwords, but not the actual search volume. (emphasis, ours)
The reason you are seeing the average monthly searches fluctuate so much is that Google is combining search volumes for related terms. In other words, you’re not actually seeing an accurate representation of how many times “SEO” is searched for. This is true across the board with their average monthly searches. No matter what keyword you are researching, you are seeing answers for a combined total rather than what you are looking for.
Google offers little help when you dig deeper into search volume. Their support page simply offers the same information, albeit less helpful and less in depth than Jones:
Average monthly searches (“Avg. monthly searches”): The average number of times people have searched for a keyword and its close variants based on the targeting settings and date range you’ve selected. By default, we average the number of searches for the term over a 12-month period.
So what can you do to narrow this search volume down further and get a more accurate reading?
The Keyword Explorer Tool:
In order to actually get the answers you’re looking for, you have to turn your attention to paid tools. While we are going to focus on Moz’s keyword explorer tool, there are others that offer similar information – for a monthly fee. There are a number of differences between what Google keyword planner suggests and Moz. The difference lies in how they sift through search volume. As Jones further explains:
Moz’s Data Range is different. Technically, our range is meant to show you a range that would contain or be lower than the expected volume for 6 or more months out of the year. I know that is a little confusing, but what it means is that you can be confident to receive at least that many impressions most months out of the year. This will become more useful when we start relaying historical trend data, but the goal is that you won’t be caught off guard by seasonal trends. (emphasis, his)
This means that, purposefully, Moz offers you lower search volume than Google keyword planner because it is pre-preparing for fluctuations throughout the year. Web traffic is influenced, in part, by seasons, events, and other factors outside of your control. While Google also uses similar historical data, they tend to side on the most search volume possible (hence the reason they claim SEO can bring in total searches between 100 thousand and 1 million).
Jones continues:
Moz’s volume metric is intentionally conservative. . . For example, we correct against high outliers more than low outliers. If GKP gives us back a volume of 10,000,000 for a keyword our clickstream data only shows 100 searches on, we are going to throw it out for the purpose of building our traffic model. The reason we do this is because of GKP combining words together in their volume estimates. If you request certain misspellings like Facbook, Google will give you the Facebook number. We don’t want that to negatively impact our model, so we aggressively root out those outliers. However, we aren’t as aggressive at rooting out outliers in the opposite direction, because there is no clear bias in that direction in GKP’s data set. The conservative numbers we present, though, should elicit confidence in the sense that you know you aren’t chasing a keyword with less volume. (emphasis, his)
In other words, while Google keyword planner takes stock of misspellings and counts that towards total search volume, Moz removes that information from their search volume. Again, this allows the user to see a more accurate representation of search volume for the keyword they are actually searching for. It’s the reason why Moz suggests “SEO” gets significantly less traffic than Google:

Using This Information:
Whether you choose to pay for paid tools is really up to you, and as we discussed earlier, Google keyword planner can be a fantastic tool. As long as you understand that the search volume you are seeing isn’t quite indicative of the true search volume, you should be pretty good. It’s also worth noting that just because you rank high for one term doesn’t mean that you automatically rank high for similar terms. You should really optimize for all keywords if you are planning on seeing traffic for them.
An often over looked section in both Google’s keyword planner and Moz’s keyword explorer is the difficulty ranking. While Google’s difficulty is based on how many businesses are advertising for that keyword, Moz’s difficulty is directly linked to how hard it will be to organically rank for that keyword. Both are useful in their own ways.
Google offers insight into how much people are currently paying to appear on their search engines, which in turn gives you a sense of how difficult it will be to organically rank for the keyword. If people are paying outrageous fees to appear on the first page of Google, imagine how much work needs to be done to rank organically for it. Moz is pretty upfront about this information and it most certainly should be considered when building an SEO strategy around a specific keyword.
Now that you have a better idea of what goes into Google keyword planner, hopefully you can use it to an even better degree. Just understand that no tool is perfect and nothing will give you the exact number. It’s why these tools are constantly being updated. If you need help understanding this information further, please think about hiring an SEO and SEM professional.