You are able to see you YouTube earnings report in your account. Earning reports can change for various reasons. 

  • Strong Campaigns: When advertisers have a strong interest for posting advertising, your RPM will be higher. For example in December when it is the Christmas period  RPM is higher and lower earnings in January when advertisers have less demand for ads.
  • Ad type: The RPM in your report is typically an average across all the different ad units that YouTube offers. Some advertisers may choose to pay per thousand views, while other advertisers choose to pay only when a viewer takes a specific action on their ad (like clicking on it).