The Complete Guide to Google Ads Bidding Strategies in 2025
The bidding landscape for Google Ads is still changing quickly. What was considered "best practice" a year ago may already be out of date, and automation has made it easier to handle today. Marketing managers and agencies who want to become experts at Google Ads bidding in 2025 must know when to utilize various tactics, such as Target CPA or Target ROAS, and when to take manual control.
The article delves deeply into the latest trends in bidding, how automation is changing the way ads work, and how to strike a balance between optimization and control for a higher return on investment.
Overview of the 2025 Bidding Landscape
The new standard as of 2025 is Google's automation-first strategy. Although manual bidding is still used, Smart Bidding has taken over the platform's performance ecosystem. Google Ads’ machine learning models are now even more responsive thanks to recent changes that draw on broader contextual signals like device, audience intent, location data, and past activity.
Simply put, automatic bidding offers scalability and precision (as long as your data and conversion tracking are clean), whereas manual bidding offers control.
Some of the biggest 2025 changes marketers should note:
Greater emphasis on Smart Bidding - Automated strategies like Maximize Conversions and Target ROAS now dominate most accounts, using real-time auction data, device context, and user signals.
Enhanced portfolio bidding - Agencies managing multiple campaigns now have stronger tools for shared bid strategies that align to overall budgets and KPIs.
Reduced reliance on manual bidding - While still available, manual CPC is positioned as a fallback for advertisers with niche targeting needs or those in highly regulated industries.
Smart Bidding vs. Manual Bidding
Though the argument between manual and smart bidding is still continuing strong, the difference between the two has grown even greater in 2025.
Manual Bidding allows advertisers to set specific CPC bids for keywords or ad groups. This gives full control but requires constant monitoring and optimization. For smaller campaigns with limited budgets or niche targeting, manual bidding can still perform well.
Smart Bidding, on the other hand, uses Google’s machine learning to optimize bids in real time for each auction. It takes into account thousands of data points — time of day, user intent, demographics, device, and historical performance — to automatically set the optimal bid.
In most campaigns, Smart Bidding outperforms manual bidding in terms of efficiency and conversion volume, particularly when used at scale. The key is feeding it good data: accurate conversions, well-segmented audiences, and enough volume to let the algorithm learn.
Use manual bidding if you:
Have low data volume or a limited conversion history
Need strict control over CPCs for budget testing
Are running awareness campaigns without measurable conversions
Use Smart Bidding if you:
Have steady conversion data
Need to scale fast across multiple networks or geos
Want to automate and optimize for specific results (CPA, ROAS, etc.)
When to Use Target CPA vs. Target ROAS
The two most popular Smart Bidding strategies, Target ROAS (Return on Ad Spend) and Target CPA (Cost Per Acquisition), are frequently confused. The goals of your campaign and your business plan will determine which one is best for you.
Target CPA
Target CPA focuses on acquiring conversions at or below a specific cost per action. It’s ideal for lead generation campaigns or e-commerce setups where every conversion has roughly the same value.
Use Target CPA when:
Your goal is to increase the number of conversions at a fixed budget
You’re focused on lead gen, app installs, or standardized conversions
Your average order value doesn’t vary much
To succeed with Target CPA, make sure you have enough recent conversion data (ideally 30+ per month) for the algorithm to learn efficiently.
Target ROAS
Target ROAS focuses on maximizing revenue relative to ad spend. Instead of aiming for a flat CPA, it dynamically adjusts bids to achieve your desired return percentage.
Use Target ROAS when:
You’re running an e-commerce campaign with varying product values
Your goal is to maximize sales efficiency and revenue per dollar spent
You have a strong data feed and accurate revenue tracking
Target ROAS has improved in 2025 as a result of better cross-device tracking and revenue modeling. Algorithms usually take a few weeks to stabilize performance; therefore, patience is necessary.
Portfolio Bidding Strategies for Multiple Campaigns
Portfolio Bidding is still a strong but underutilized tool for agencies and big marketers running several campaigns.
You can combine several campaigns, ad groups, or keywords under a single Smart Bidding strategy by using portfolio bidding. By learning from a bigger dataset, Google's algorithm can optimize for common objectives like Target ROAS or Maximize Conversions across campaigns.
Why it matters:
More data means better algorithmic decisions
You can control overall performance at a portfolio level instead of micromanaging each campaign
It smooths out budget fluctuations between campaigns
Setting a shared Target ROAS portfolio, for instance, can assist Google in dynamically allocating spend where the highest-value conversions are occurring if you oversee three campaigns for comparable products.
When using Portfolio Bidding:
Ensure campaigns have similar goals and conversion types
Monitor shared performance metrics to avoid one campaign consuming all the budget
Use performance-based bid caps if you need guardrails
Common Bidding Mistakes and How to Avoid Them
Even experienced marketers can make critical errors when managing Google Ads bidding. Some of the most common mistakes include:
1. Switching strategies too soon.
Learning how to bid smartly takes time. Avoid switching tactics or goals too often, as this can reset learning processes.
2. Poor conversion tracking.
A poorly defined or tracked conversion rate will cause Smart Bidding to optimize for the incorrect objectives. Make sure all tracking is accurate using GA4 or Google Tag Manager.
3. Using too many overlapping bid strategies.
Combining multiple automated strategies across similar campaigns can cause internal competition and drive up CPCs.
4. Setting unrealistic targets.
You can't achieve a target ROAS of 900% if your historical average is 300%. Set attainable goals and make little adjustments over time.
5. Ignoring seasonality adjustments.
Use the Seasonality Adjustment tool for sales periods or events to give Smart Bidding context.
Case Study: Scaling with Target ROAS and Maximize Conversions
A digital agency managing a mid-sized e-commerce brand tested multiple bidding strategies over three months in late 2024.
Campaign 1 (Manual CPC): Averaged 2.3 ROAS at $1.10 CPC
Campaign 2 (Target CPA): Achieved 3.1 ROAS but limited volume
Campaign 3 (Target ROAS): Reached 5.4 ROAS with 40% higher conversions
Campaign 4 (Maximize Conversions with Portfolio): Drove 27% lower CPA overall
By consolidating similar campaigns into a Portfolio Target ROAS strategy, the brand increased total conversion value by 48% while reducing total ad spend by 12%. Over time, the learning phase stabilized performance further, proving that with enough data and patience, Smart Bidding can outperform manual optimization consistently.
Final Takeaways
In 2025, patience, plan alignment, and high-quality data are key components of successful Google Ads bidding. Automation has evolved into a complex, data-driven system that rewards carefully planned campaigns and reliable tracking, not a quick fix.
For marketing managers and agencies, the focus should be:
Build clean, conversion-rich data
Choose Smart Bidding strategies that fit your business goals
Use Portfolio Bidding for cross-campaign optimization
Monitor performance, but don’t overreact to short-term fluctuations
Google's Smart Bidding, when properly configured, can help you reach your target ROAS, increase conversions, and expand campaigns effectively, allowing your team to concentrate on strategy rather than spreadsheets.
