Meta Ads Budget Optimisation: CBO vs ABO
The battle rages on. ABO (Ad Set Budget Optimization): You tell Facebook exactly how much to spend on each audience. CBO (Campaign Budget Optimization): You give Facebook a pot of money, and it decides who gets it.
Facebook (Meta) pushes CBO hard. They call it "Advantage+ Campaign Budget." But is it actually an advantage? The answer is: It depends on your goal.
The Rules of Engagement
When to use ABO (Control)
Use ABO for Testing.
- Scenario: You want to test Audience A (Broad) vs Audience B (Lookalike).
- Why: If you use CBO, Facebook will dump 90% of the budget into the larger audience (Broad) because it's easier to spend money there. It won't give Audience B a fair chance.
- Strategy: Set $50/day on Ad Set A and $50/day on Ad Set B. Force the test.
When to use CBO (Scale)
Use CBO for Scaling.
- Scenario: You have 3 winning audiences and you want volume.
- Why: Facebook's algorithm is smarter than you in real-time. It knows that on Tuesday morning, Audience A is cheap, but on Wednesday night, Audience B is better. CBO flows like water to the path of least resistance.
- Strategy: Set $1,000/day at the Campaign level. Let the machine drive.
The "Hybrid" Structure (The Pro Move)
The best media buyers use both.
- Testing Campaign (ABO): This is your laboratory. Test new creatives and audiences here.
- Winners Campaign (CBO): This is your bank. Once an ad/audience wins in the ABO campaign, duplicate it into the CBO campaign to scale.
The "Min/Max" CBO Trick
You can force CBO to behave. If you have a CBO campaign but one ad set is starving:
- Go to the Ad Set level.
- Edit "Ad Set Spend Limits."
- Set a Minimum Daily Spend (e.g., $50).
- This forces CBO to spend at least $50 on that audience, while still optimizing the rest.
Summary
- ABO = Science. Use it to prove a hypothesis.
- CBO = Business. Use it to make money once the hypothesis is proven.
Do not scale with ABO. You will micromanage yourself to death. Do not test with CBO. You will get false negatives. Respect the roles.
About the Author
Performance marketing specialist with 6 years of experience in Google Ads, Meta Ads, and paid media strategy. Helps B2B and Ecommerce brands scale profitably through data-driven advertising.
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