Internet traffic is like an ocean. Some days, there will be small waves. Other days, there will be big ones. So, if your ads don't show up much because of low traffic, then we'll make up for that by showing them more when traffic's higher.
That's why we allow up to 2 times the clicks in a day than your average daily budget allows for campaigns that aren't paying for conversions. This is called overdelivery. And it's a good thing: if we end up showing your ad too much -- to the point where you accrue more costs than your average daily budget allows for over a billing cycle -- then we'll give you a credit for those extra costs.
As we mentioned, you might see that your advertising costs each day are a little higher or lower than what you set for your average daily budget. If you do, don't worry -- over a month-long billing cycle, you won't be charged more than your average daily budget would've allowed for over 30.4 days.
Let's explain that number.
Basically, 30.4 is the average number of days in a month (365 days in a year / 12 months = 30.417). Google multiplies your average daily budget by this number so that we know what your budget should be over the course of a month.
Let's say that you set your budget at $5 a day and your billing cycle is 30 days. Over the course of the month, you notice that your charges vary. Some days you're charged $2, on others you're charged $10. But at the end of the month, your charges won't exceed $152 (that's 30.4 multiplied by your $5 budget). So even though your campaign costs tipped above and fell below your $5 budget from day to day, at the end of the month you're still charged no more than what you budgeted.
The waves of Internet traffic might make your daily costs go up and down. But at the end of the month, despite those unpredictable waves, you'll find your costs right where you expected them to be.
Check for overdelivery
Sometimes we deliver over your monthly budget. In those cases, we'll credit the overdelivery cost back. If you'd like to see whether we've given you overdelivery credits, follow these steps:
- Sign into your Google Ads account.
- From the upper right-hand corner of your account, click the reports icon .
- Under "Predefined reports (Dimensions)" drop down menu, select Other, then click Billed cost.
You’ll see a report that lists served and billed costs for each campaign. To calculate overdelivery, subtract 'Billed cost' from 'Served cost'. To perform these calculations in bulk, click the download icon on the top right of the report and save as a .csv file.
By default, the data is displayed daily and sorted by served cost. If you wish to see for a certain date range, remove the “Day” filter and set a date range in the upper right-hand section above the table.
Will overdelivery of my average daily budget increase the maximum that I can be charged for the month?
No. The monthly charging limit remains unchanged. Even though you may see higher spend on some days, this overdelivery is balanced by days of the month when your spend is below your average daily budget.
There are no changes to how spend is prioritised throughout the month. Google Ads will continue to optimise your spend based on daily fluctuations in traffic, what you've spent on previous days of the month, and other factors.
In general, spend may exceed your average daily budget on days that are more likely to drive clicks and conversions.
If your campaign isn’t limited by budget, your monthly spend will remain the same. There are no changes to how campaigns that aren’t limited by budget work.
If your campaigns are limited by budget for one or more days in the month, then you’ll see some variation in your daily spend. However, you’ll never be charged more than the monthly charging limit. Flexibility in your budget helps balance days with low traffic by increasing spend on days that are likely to drive more clicks and conversions.
Learn more about what it means to be limited by budget
It’s unlikely that your spend will be twice your average daily budget for multiple days in a row. For 'standard' ad delivery, Google’s budgeting algorithm optimises delivery based on your past spending within the billing cycle. This helps keep your ads delivering throughout the month. Learn more about ad delivery.
There’s no change to how adjusting your budget impacts what you’ll be charged for the rest of the month. As before, when you change your budget, your spend for the rest of the month won’t exceed your new average daily budget multiplied by the remaining days in the month.
For example, let’s say that you set an average daily budget of $10 on the first day of September, and you change it to $20 on day 16. For the first 15 days of the month, your spend will be capped by your monthly charging limit of $10 * 30 (number of days in September). After changing your average daily budget to $20, your spend for the rest of the month will be $20 multiplied by the remaining 15 days.
For the first 15 days of the month, your spend may be more than half your monthly charging limit. This is because spend may exceed your average daily budget on some of those days. However, as soon as you change your budget, you won’t be charged more than $20 multiplied by the remaining days in the month. If you already had ad spend on 16 September before you changed your budget, your total spend from 16–30 September could be slightly higher than $300.
Learn more about why costs might exceed your average daily budget
There’s no opt-out. Overdelivery is designed to help you optimise spend for days of the month when you’re more likely to get clicks and conversions.
No. You won’t be able to place a cap on your daily spend using your campaign’s average daily budget.
There are no changes to how 'accelerated' ad delivery works. 'Accelerated' ad delivery spends your average daily budget faster. As such, your spend will be spread less evenly throughout the day, and overdelivery is more likely. We recommend using 'standard' delivery if you’d like to ensure that your spend is spread evenly throughout the day.
Currently, you can't set a monthly budget within Google Ads. However, you can use your average daily budget multiplied by the number of days in the month to determine what your monthly spend will be. Learn more about campaign budgets.