Over the years, many of you have told us that you'd like to be charged a consistent amount each calendar month. We're happy to help you by introducing a monthly charging limit for campaigns, which is automatically calculated based on your daily budget.

When your daily budget is unchanged throughout an entire calendar month, We'll set a monthly charging limit for that campaign by multiplying your daily budget by 30.4, which is roughly the average number of days in a month (365 days in a year / 12 months = 30.417 days/month). For example, if your daily budget is US$10 throughout a month, you won't be charged more than $304 during that month (US$10 daily budget * 30.4 average days per month). As usual, actual daily spend may vary.

Accounts will transition to monthly charging limits over the next several weeks. When you edit your budget from Campaign Settings, a new tooltip will also be visible describing this change.

To learn more about this change, please see our FAQs on the monthly charging limit and on what happens when you change your budget.

Posted by Dan Friedman, Inside AdWords crew