CBO or ABO in 2026: when each one wins and the rule for switching

Leonardo Barbosa · 2026-10-07

CBO DISTRIBUTES, ABO GIVES YOU CONTROL; TEST IN ABO, SCALE IN CBO

CBO (Campaign Budget Optimization) and ABO (Ad Set Budget Optimization) serve different purposes. CBO automatically distributes the budget across ad sets, aiming for the best performance. ABO, on the other hand, gives you tighter control over each ad set, making it ideal for testing. So, start your tests in ABO, where you can adjust and optimize your campaigns at a more granular level. Once you find an ad set that performs well, move the budget to CBO and scale the campaign.

CBO minimum budget limits per ad set

When using CBO, it’s essential to respect the minimum budget limits, which generally range from 10% to 30% of the campaign’s total budget. This ensures the algorithm has enough data to optimize delivery. If your total budget is R$1.000, for example, each ad set should receive between R$100 and R$300.

When CBO puts 90% into one ad set and what to do

If you notice that 90% of the CBO budget is going to just one ad set, it means that ad set is performing much better than the others. In that case, consider increasing its budget or creating new, similar ad sets to diversify and reduce risk. It’s also important to monitor performance and, if needed, adjust the targeting or creative in the ad sets that aren’t performing as well.

Numbers: 3 to 5 ad sets, 20 to 30% increase every 48h

For a solid strategy, keep 3 to 5 ad sets in your CBO. This gives the algorithm enough variations to test without losing focus. When scaling, increase the budget by 20 to 30% every 48 hours while keeping a close eye on results. This gradual approach helps avoid sharp performance swings.

Mistake: mixing cold and warm audiences in the same CBO

A common mistake is mixing cold (new) and warm (retargeting) audiences in the same CBO. This can dilute performance because the algorithm may prioritize the audience that generates more conversions, hurting results from the cold audience. To avoid this, create separate CBOs for each audience type, allowing for more effective optimization.

And you, how many ad sets do you usually use in your campaigns, and what’s your monthly increase percentage?