Ad glossary
Campaign budget optimization (CBO)
A Meta setting that applies one budget at campaign level and spreads it across ad sets automatically, now called Advantage campaign budget.
Campaign budget optimization, or CBO, is a Meta setting where you set a single budget at the campaign level instead of giving each ad set its own budget. Meta then distributes spend across the ad sets in that campaign in real time, aiming to get the most results for the budget based on your bid strategy. Meta has since renamed the feature Advantage campaign budget, though many advertisers still call it CBO.
CBO versus ABO
The alternative is ad set budget optimization, often called ABO, where you set a budget on each ad set individually.
- CBO suits campaigns where you want the system to find the best-performing ad sets and you are comfortable with uneven spend.
- ABO gives you more control over how much each ad set receives, which some teams prefer for structured creative testing or when trying new audiences.
Things to know
- With CBO, spend is rarely split evenly. One ad set may receive most of the budget while others receive very little.
- You can set minimum and maximum spend limits on individual ad sets, although heavy use of limits reduces the benefit of automation.
- Budget changes at campaign level can affect the learning phase of the ad sets underneath.
In practice
Many accounts use both approaches: ABO or a dedicated testing setup to give new ideas a fair chance, and CBO or Advantage+ campaigns to scale proven winners. Whichever you choose, judge results at the campaign level, since the system is optimising the campaign as a whole.
Last reviewed Oct 27, 2026