What Is a CBO Campaign and When Should You Use One

In our last article, we covered building a campaign in PAUSED state and starting with CBO. Here we go deeper into how CBO actually works, and when ABO is the better choice.

The Difference Between CBO and ABO

CBO (Campaign Budget Optimization) sets the budget at the campaign level, and Facebook decides in real time which ad set is performing best — that ad set automatically gets more of the budget.

ABO (Ad Set Budget Optimization) fixes each ad set’s budget manually, regardless of how it’s performing.

When to Use CBO

• When you have 3 or more ad sets testing similar audiences
• When you want Facebook to automatically allocate spend to the best-performing combination
• When your daily budget is large enough (at least $15–20/day) to give the algorithm room to learn

When ABO Is Better

• When you want to give different audiences equal exposure — for example testing multiple countries or cities where each one needs a guaranteed minimum spend
• When the budget is too small and CBO would dump it all into one ad set, starving the rest
• When you deliberately want to test a new creative without it stealing budget from ad sets that are already working

A Common Mistake

New advertisers often turn CBO on and immediately launch several untested audiences under one campaign. The result: Facebook doesn’t have enough data to learn from, and spend gets wasted.

A better approach: test 2–3 ad sets individually with a small ABO budget first, then combine whichever performs best into a CBO campaign.

Respect the Learning Phase

Every new ad set or campaign goes through a “Learning Phase” — performance can be unstable during this time. Wait until you have at least 50 optimization events (like purchases) or about 7 days before judging results.

This Applies Across Any Market

These principles come from how Facebook’s algorithm actually works, not from any one country or market — so whether you’re running campaigns from anywhere in Asia, the same logic applies. Just adjust currency, budget range, and audience size to your local market.