Introduction
Campaign Budget Optimization (CBO) is a feature in advertising platforms (especially Facebook Ads, but also conceptually in Google Ads) where the platform automatically distributes a single budget across multiple ad sets or ad groups within a campaign to maximize performance. In Google Ads, a similar concept is known as Shared Budget, where a single budget is applied to multiple campaigns, and Google optimizes spend based on performance and opportunity. Knowing when to use budget optimization features like CBO or Shared Budgets is crucial to ensure your budget is spent efficiently, especially if you’re managing multiple campaigns or ad groups.
What Is Campaign Budget Optimization (CBO)?
CBO automatically allocates your total campaign budget across ad sets (in Meta/Facebook) or across multiple campaigns (in Google Ads with Shared Budgets) in real time. It prioritizes top-performing segments, minimizing waste and improving return on ad spend (ROAS).
In Google Ads, Shared Budgets work similarly by
– Distributing spend dynamically among selected campaigns
– Maximizing performance where there’s most opportunity
– Reducing underspending or overspending across individual campaigns
When to Use Campaign Budget Optimization or Shared Budgets
1. When Managing Multiple Campaigns with Similar Goals
If you’re running several campaigns that aim for the same objective—like conversions, traffic, or leads—CBO or Shared Budgets help Google distribute the total budget where it’s most effective.
Example:
If you have three campaigns promoting different product categories (e.g., shoes, bags, and accessories), and all aim to drive sales, Google will dynamically allocate more budget to the product category that’s performing best at any given time.
2. When Some Campaigns Frequently Underspend
Sometimes individual campaigns don’t spend their daily budget fully due to limited search volume or low bids. By using a Shared Budget, Google reallocates unused funds from one campaign to another that can spend more effectively.
3. When You Want Simpler Budget Management
Rather than manually setting and adjusting budgets for each campaign, Shared Budgets make your budget management easier. You set one combined daily budget, and Google handles the rest.
4. During Testing Phases or Experimentation
When testing multiple audiences, keywords, or ad formats, you might not know upfront which will perform best. CBO allows the algorithm to find the winning segment by shifting more spend toward top performers.
5. When Traffic Is Seasonal or Volatile
In industries like fashion, travel, or retail, demand often shifts daily or weekly. Shared Budgets help adapt to traffic fluctuations by dynamically moving budget where it’s needed without you having to manually adjust it every time.
6. When Using Performance Max or Smart Campaigns
These campaign types already include budget optimization by default. If you’re running multiple Performance Max campaigns, you can use Shared Budgets to allow Google to optimize across them.
7. If You’re Using Automated Bidding Strategies
Campaigns using strategies like Maximize Conversions or Target CPA benefit more from budget optimization. These bidding algorithms work best when not restricted by strict budgets, and Shared Budgets give them more flexibility.
8. For Brand vs. Non-Brand Keyword Allocation
If you’re unsure how much to allocate to brand keywords (like “Zara shoes”) vs. generic ones (like “black heels”), Shared Budgets let Google allocate automatically based on conversion potential and search volume.
9. For New Advertisers With Limited Budgets
If you’re starting with a small budget and want maximum efficiency without constantly adjusting things manually, budget optimization lets you “set and forget” while still learning what performs best.
10. When Running Geographically Split Campaigns
If you have campaigns targeting different regions (like Delhi, Mumbai, Bangalore), and traffic volumes vary, Shared Budgets will ensure that high-demand areas get more budget dynamically.
When NOT to Use Budget Optimization or Shared Budgets
1. When You Want Strict Budget Control per Campaign
If you need to ensure that each campaign gets exactly ₹500 per day—no more, no less—then Shared Budgets aren’t for you. Google may prioritize one campaign over another.
2. When Campaign Objectives Are Very Different
If one campaign is focused on brand awareness and another on direct sales, it’s better to keep budgets separate. Budget optimization won’t be able to prioritize accurately between such different goals.
3. When Performance Is Already Optimized at the Campaign Level
If you’ve already fine-tuned individual campaign performance, adding Shared Budgets may disrupt that balance. In such cases, keeping separate budgets allows you to maintain consistency.
4. During Highly Time-Sensitive Campaigns
If you’re running a one-day promotion or flash sale, and each product category must get equal visibility, you should control budgets individually rather than letting the algorithm choose.
5. If One Campaign Has Very Limited Search Volume
If one of your campaigns targets very niche keywords, Shared Budget might allocate too little to it because it’s not delivering high performance compared to broader campaigns. This could limit visibility for important but low-volume queries.
Example: Campaign Budget Optimization for Myntra
Myntra runs campaigns for three categories:
– Footwear
– Casual wear
– Premium ethnic wear
They use separate campaigns but apply a Shared Budget of ₹20,000 per day. On weekdays, casual wear gets more traffic, and Google allocates ₹10,000 to it. But on weekends, ethnic wear picks up, and budget automatically shifts in its favor. Over time, Myntra sees a 20% increase in conversions and a 15% decrease in CPA compared to separate static budgets.
Conclusion
Campaign Budget Optimization or Shared Budgets in Google Ads can improve campaign efficiency, reduce manual work, and help you get the most out of your total budget. It’s ideal when your campaigns have shared goals, variable performance, or need more automation. However, if you require strict control, have differing objectives, or are running time-sensitive promotions, keeping budgets separate may be better. Like most tools in Google Ads, the key is to align your budget structure with your goals, test regularly, and adapt based on results.
