What Google says
In Google's own words, Keyword Planner lets you "discover new keywords related to your business and view estimates of the searches they receive and the cost to target them." You find it in the Tools menu, and you need billing details entered to use Discover new keywords. (Google help center)
Reading the columns correctly
Average monthly searches is the number of times people searched a keyword and its close variants, and Google shows these historical stats for exact matches only, so the figure is the same whichever match type you pick. Competition is advertiser competition: the number of advertisers that showed on a keyword relative to all keywords on Google. Top of page bid low and high ranges approximate the 20th and 80th percentile of what advertisers paid. (Google help center)
Why it beats an SEO keyword list for ads
SEO tools are built to help content rank. Keyword Planner sizes paid demand. We build ad keyword lists from it, add the survivors as phrase match, and check the forecast before writing a category off, as we explain in SEO tools size content. Keyword Planner sizes ad demand.
A demand check before you spend
Five minutes in Planner tells you whether the searches exist. If they don't, no bidding strategy will fix it, which is the point of Search ads don't create demand. If they do and a campaign still produces nothing, the problem is the campaign.
Common questions
What is Google Keyword Planner?
Keyword Planner is a free tool inside Google Ads that suggests keyword ideas for Search campaigns and estimates their monthly searches and the cost to target them. It also builds forecasts of clicks and cost for a keyword plan, and conversions if conversion tracking is set up.
Is Keyword Planner volume exact match?
Yes. Google says average monthly searches counts a keyword and its close variants, and historical stats are shown for exact matches only. Forecasts of clicks and cost do take the selected match type into account.
What does competition mean in Keyword Planner?
It measures advertiser competition: the number of advertisers that showed on a keyword relative to all keywords across Google, shown as low, medium or high. It is not an SEO difficulty score.
Do I need to spend money to use Keyword Planner?
You need to complete account setup with billing information to use features like Discover new keywords. In our experience, accounts with little or no active spend often see search volume as a range, such as 100 to 1K, rather than an exact figure.
Why can't I find some keywords in Keyword Planner?
Google says keywords with very low search volume, or keywords considered sensitive, aren't discoverable or forecastable, and its privacy policies often prevent results in categories like health or finance.