Most Google Ads accounts use the wrong bidding strategy — not because the advertiser is careless, but because Google’s interface steers you toward automation before your account is ready for it. Here’s how each bidding strategy actually works, what data it needs, and when it makes sense to use it.
The Core Difference: Manual vs. Automated Bidding
Manual CPC means you set the maximum you’re willing to pay per click at the keyword level. Google doesn’t adjust it based on conversion likelihood. You’re in control, but you’re also flying without the machine learning layer.
Automated bidding means Google’s algorithm adjusts your bids in real time based on auction signals — device, time of day, location, audience membership, search history, and more. The problem: automated bidding is only as good as the conversion data feeding it. Without enough signal, the algorithm guesses.
That’s the thing Google won’t tell you upfront.
Manual CPC: The Starting Point for New Accounts
Manual CPC gives you precise control over spend at the keyword level. You set a max bid; Google won’t exceed it. Enhanced CPC (eCPC) is a mild automation layer on top — it adjusts bids up or down by up to 30% based on conversion likelihood.
When to use it: New accounts with no conversion history. Accounts with fewer than 30 conversions per month. Situations where you need strict budget discipline.
The downside: You miss bid adjustments that would have won you profitable clicks. You also need to manage bids manually as competition shifts.
Target CPA: Only Works With Enough Conversions
Target CPA tells Google to bid automatically to hit a target cost per acquisition. If your target CPA is $50, Google tries to get conversions at that price or below.
Here’s the requirement Google buries in fine print: you need at least 50 conversions in the last 30 days before Target CPA becomes reliable. Below that threshold, the algorithm doesn’t have enough signal. It will swing bids erratically and either underspend or blow past your target.
Start with a target CPA 20–30% higher than your historical average. Give the algorithm 2–4 weeks to exit the “learning period” before judging performance.
Target ROAS: Higher Ceiling, Higher Requirements
Target ROAS (return on ad spend) optimizes for revenue rather than conversion volume. If you want $4 back for every $1 spent, set a target ROAS of 400%.
The data requirement is steeper here. Google recommends at least 50 conversions in the last 30 days, but in practice accounts with fewer than 100 monthly conversions struggle. Target ROAS also requires that you’re passing conversion values — not just tracking conversions as equal events, but assigning actual revenue values to each one.
If you’re running WooCommerce or Shopify, this is achievable with proper conversion tracking setup. If you’re a service business tracking form fills, you’ll need to assign static conversion values or use a different strategy.
Maximize Conversions: Aggressive Budget Spending
Maximize Conversions tells Google to get as many conversions as possible within your daily budget — without a cost target. It’s useful for campaigns that chronically underspend, or for accounts in the early stages of collecting conversion data.
The risk: it will spend your full budget even if the cost per conversion is terrible. Use it as a learning-phase strategy, then shift to Target CPA once you have enough data.
Maximize Conversion Value is the revenue-focused equivalent — same idea, but it optimizes for total conversion value rather than volume.
Maximize Clicks: For Traffic, Not Conversions
Maximize Clicks is designed to drive as much traffic as possible within your budget. It’s not a conversion strategy. Use it if your goal is brand awareness, remarketing list building, or testing new landing pages at volume.
Left unsupervised, Maximize Clicks will chase cheap clicks — which often means low-intent traffic. Set a max CPC cap to prevent the algorithm from buying junk at any price.
Target Impression Share: For Brand and Defensive Campaigns
Target Impression Share bids to show your ads at a specified frequency — top of page, absolute top, or anywhere on the results page. You set a target percentage (e.g., 80% of eligible impressions) and Google adjusts bids to hit it.
This is rarely the right strategy for performance campaigns. It makes sense for brand campaigns (bidding on your own name) or competitor campaigns where visibility matters more than cost efficiency.
Portfolio Bid Strategies: Managing Multiple Campaigns
Portfolio bid strategies apply a single shared bidding strategy across multiple campaigns. They’re useful when you want to pool conversion data — a campaign with 20 conversions and a campaign with 35 conversions can share data to hit the 50-conversion threshold together.
This is an underused feature, especially for accounts with many small campaigns in the same business category.
The Learning Period: What Happens After You Switch Strategies
Every time you change your bidding strategy — or make a significant change to budget, targeting, or conversion actions — Google enters a learning period. During this time, the algorithm is recalibrating its predictions based on the new setup. Expect 1–3 weeks of erratic performance: CPAs will be inconsistent, conversion volume will fluctuate, and spend may be uneven.
This is normal. What’s not normal is assuming the new strategy isn’t working after three days and changing it again. Every change restarts the learning period. Accounts that make rapid, reactive changes never give any strategy a fair trial — and they accumulate fragmented data that makes optimization harder over time.
Set a rule for yourself: after any bidding change, commit to a two-week observation window with no further changes before evaluating results.
Bid Adjustments: Manual Modifiers on Top of Your Strategy
Whether you’re on manual CPC or smart bidding, bid adjustments let you increase or decrease bids based on signals: device type, location, time of day, and audience membership.
Device adjustments: If mobile converts at 3x the CPA of desktop, reduce mobile bids by 40–50%. If mobile converts better, increase them.
Location adjustments: If campaigns run nationally but certain states consistently convert at higher CPAs with zero revenue, reduce those locations’ bids or exclude them entirely.
Time of day adjustments: Service businesses often convert during business hours. Running ads at midnight at full bid wastes budget. Use ad scheduling to reduce bids by 80–90% during non-converting hours.
Smart bidding incorporates these signals automatically — but manual and eCPC accounts benefit significantly from deliberate bid adjustment management.
How to Choose the Right Strategy
The decision tree is simpler than Google makes it look:
- New account, no conversion data: Start with Manual CPC or Maximize Conversions (capped).
- 30–50 conversions/month: Enhanced CPC or Maximize Conversions.
- 50+ conversions/month: Test Target CPA.
- 100+ conversions/month with revenue values: Test Target ROAS.
- Brand/competitor campaigns: Target Impression Share or Manual CPC.
Don’t let Google auto-apply Smart Bidding during campaign setup if you don’t have the conversion volume to support it. The recommendation dialog is aggressive. It’s also pushing you toward strategies that benefit Google’s revenue as much as yours.
If you’re unsure whether your current bidding setup is costing you money, Honest can audit your account and flag the specific issues. It takes about three minutes.
FAQ
What is the minimum conversion volume for smart bidding? Google’s official minimum is 30 conversions in 30 days for Target CPA, but performance is unreliable below 50. Target ROAS works better with 100+ monthly conversions.
Can I switch bidding strategies mid-campaign? Yes, but each switch resets the learning period — typically 1–2 weeks. Avoid switching strategies repeatedly. Each reset means inconsistent data and unpredictable performance.
What is Enhanced CPC? Enhanced CPC (eCPC) is a manual CPC variant where Google adjusts your max bid up or down by up to 30% based on predicted conversion likelihood. It’s a light automation layer — a reasonable middle ground for accounts not yet ready for full smart bidding.
Why does my Target CPA campaign overspend? Target CPA averages out over time — not per click. Google may pay $80 for one conversion and $20 for another, targeting a $50 average. Daily spend can also spike above your daily budget by up to 2x on high-converting days, balanced by underspend on other days.
Should I use Manual CPC or Smart Bidding? If you have fewer than 50 conversions per month, manual or lightly automated bidding (eCPC) will usually outperform smart bidding. Smart bidding with thin data is effectively random bidding with extra steps.
What happens during the smart bidding learning period? Performance fluctuates as Google calibrates. Expect higher CPAs and erratic conversion volume for 1–2 weeks. Resist the urge to change settings during this window — each change resets the clock.
Does bidding strategy affect Quality Score? No. Quality Score is based on expected CTR, ad relevance, and landing page experience — not your bid strategy. But your bid strategy determines how aggressively you compete in auctions, which affects impression volume and the data your account accumulates.
Our Google Ads management includes campaign builds with the right bidding strategy matched to your conversion volume — not the one Google defaults to. See what’s included in our fixed-price packages.