Google Keyword Planner is a tool offer by Google. I just want to tell you that it's a free tool provided by Google, which help us to find keywords that is related to our business or blogging. Whenever you type a keywords by this tool then its show the all the keywords related to that keyword and its also show that how many time that keyword search by the customers or by the peoples. With the help of Google Keyword Planner you can find a keyword in a specific Country. For example you just type a keyword like "SEO" and press search button than Google Keyword Planner show some result regarding keyword "SEO" but if you want to know that in "XYZ" country how many times keyword "SEO" search than click on the country option given in search option and select the specific country, Now Google Keyword Planner tool show the result for that specific country.
It helps us to rank our site or blog just because if we know that which type of keyword rank on top than we choose the keyword that similar to that keyword which is already within top rank. In another way it help us to understand that on which topic we have to write for example if we write a keyword which is searched very less time its means we can write on that topic in different way and its also make more possibilities to rank up because which topic we selected on that topic we have less competitors.