It is important to know the difference between your budget and your amount spent with Facebook Advertising.
: The amount of money you’re willing to pay to have ads from your ad set shown over the period you set it to run. You set a budget for each ad set
you create. Remember:
You’re not buying ads or the ability to show ads. You’re telling Facebook how much you’re willing to spend on them showing your ads to people in your target audience who can get you the results you want.
: The amount you actually end up paying (how much money was used from the budget) on your ad set. Ideally, your ad sets will spend most, if not all, of their budgets. (If they’re not, check out these Tips from Facebook
It’s also important to know the difference between daily and lifetime budgets.
Each ad set will have a separate budget, so keep this in mind if you have more than one active ad set.
When you set your daily budget, you’re setting an average. This means that Facebook will try to get you roughly your daily budget’s worth of the result you optimized for every day. However, there may be certain days that are great opportunities to get you lots of that result. On those days, we may spend up to 25% over your daily budget.
They do this to deliver your ads and spend your budget as efficiently and effectively as possible. By allowing themselves 25% flexibility, they can more easily take advantage of great opportunities when they arise in the ad auction marketplace.
For example, if your daily budget is $10, they may spend up to $12.50 on a given day.
However, your charges will average out over a calendar week. (A calendar week is Sunday to Saturday.) If they spend more on a day with lots of opportunities for results, we’ll spend less on a day with fewer.
Wowzas! Sorry to bore you with all the background stuff but it’s best that you understand how all this works before you run an ad campaign.