There are simply so many variables to take into account that it’s impossible to come up with a single formula. Fortunately, a study from Ahrefs may be able to give you a more concrete answer to the question “How long does it take to rank in Google?”
The Ahrefs team took 2 million random keywords and pulled data on the top 10 ranking pages for each of them. Based on this thorough data analysis, the team calculated that the average top 10 ranking page is over 2 years old while pages that rank at first position are almost 3 years old.
Next, the study team tracked the position history of each of 2 million pages that were first seen by the Ahrefs crawler page for any keyword the page was ranked for. The results showed that only 5.7% of the analyzed pages ranked in the Top 10 search results within 1 year for at least 1 keyword.