Key Takeaways
- Smart Bidding now evaluates 3,847 auction-time signals in 100 milliseconds, making most manual bid adjustments redundant, but device bid adjustments of -100% remain the single override that still works across every automated strategy
- Average CPCs rose 12.88% year over year in 2025, with 87% of industries experiencing higher costs, making precise bid control more financially consequential than ever
- Campaigns using AI Max with Smart Bidding Exploration saw an 18% increase in unique converting search query categories and a 19% lift in total conversions, according to Google’s internal data
- Seasonality bid adjustments are designed for 1 to 7 day events only and should be calibrated to expected CPC increases, not conversion rate increases, a common miscalibration that can drain budgets before noon
- The only bid adjustments that function under Smart Bidding are device adjustments for Target CPA (which modify the CPA target, not the bid itself) and the universal -100% device exclusion, everything else is ignored
- Data exclusions and seasonality adjustments are the advanced bidding controls that give campaign managers strategic influence over Smart Bidding without overriding it
What Are Bid Adjustments in Google Ads, and Why Are They Misunderstood?
Bid adjustments are percentage modifiers that increase or decrease bids based on specific criteria: device, location, time of day, audience, demographics, and more. They range from -90% to +900% depending on the type (with -100% available for device exclusions). In theory, they give campaign managers granular control over when, where, and to whom their ads appear. In practice, the relationship between bid adjustments and Google’s automated bidding ecosystem has become one of the most misunderstood aspects of modern PPC management.
The confusion stems from a fundamental shift in how Google Ads operates. As recently as 2018, bid adjustments were the primary optimization tool for experienced campaign managers. You analyzed performance by device, location, and time of day, then set modifiers to push budget toward high-converting segments and away from underperformers. It was tedious but controllable.
Today, Smart Bidding strategies (Target CPA, Target ROAS, Maximize Conversions, Maximize Conversion Value) process thousands of signals per auction that human analysts cannot evaluate in real time. Google’s own documentation states that Smart Bidding evaluates 3,847 auction-time signals to set every bid. That means the algorithm is already adjusting for device, location, audience, time of day, browser, operating system, search query context, and hundreds of other variables before your manual bid adjustment even applies.
The result: most bid adjustments set by campaign managers on automated campaigns are either ignored outright or create conflicts with the algorithm’s optimization logic. And the campaigns paying the price for this confusion are the ones with the highest spend.
Which Bid Adjustments Actually Work Under Smart Bidding?
This is where the platform’s documentation gets murky, so let’s be direct. Under Smart Bidding strategies (Target CPA, Target ROAS, Maximize Conversions, Maximize Conversion Value), the vast majority of manual bid adjustments are not supported. Google’s help documentation confirms that if you make a manual bid adjustment to your automated Smart Bidding strategy, it will not be applied.
There are exactly two exceptions.
Device bid adjustment of -100%. This exclusion works across every automated bid strategy. Setting a -100% device modifier on mobile, desktop, or tablet completely excludes that device from the campaign. This is absolute. The algorithm respects it because you are not adjusting a bid. You are removing an entire device category from eligibility.
Device bid adjustments under Target CPA. This is the one that catches even experienced managers. When you set a device bid adjustment on a Target CPA campaign, you are not modifying the bid. You are modifying the CPA target for that device. A +20% device adjustment on mobile tells the algorithm you are willing to pay 20% more per conversion on mobile devices. If your Target CPA is $50, the mobile target becomes effectively $60. This is a strategic lever, but it functions differently than it does under manual CPC, and misunderstanding that distinction can quietly inflate acquisition costs.
Everything else, location adjustments, demographic adjustments, audience adjustments, ad schedule adjustments, all of it is ignored by Smart Bidding. The algorithm considers all of those signals internally and sets bids accordingly. Your overlaid modifiers are redundant noise.
Do Bid Adjustments Still Matter for Manual CPC Campaigns?
Absolutely. For campaigns running Manual CPC (with or without Enhanced CPC), bid adjustments remain the primary optimization mechanism. Google adheres to your manual bids plus all applied adjustments, never bidding more than the cumulative maximum.
The catch is that manual bidding makes strategic sense in fewer and fewer scenarios. In 2026, manual CPC is generally appropriate for brand keyword campaigns where you want predictable cost control, test campaigns with zero conversion history, or training and diagnostic scenarios where you need to understand baseline performance before layering automation.
If a campaign has consistent conversion volume (30 or more conversions per month, ideally 50 or more), the data overwhelmingly favors Smart Bidding. Google’s algorithm processes device, location, time, audience, search context, weather, seasonality, and thousands of other contextual variables for every single auction. Manual bidding treats every auction identically. The performance gap between those two approaches widens as conversion volume increases.
For campaigns that remain on manual bidding, the eight available bid adjustment types still function exactly as documented:
- Device: -100% to +900%, campaign or ad group level
- Location: -90% to +900%, campaign level only
- Ad schedule: -90% to +900%, campaign level only
- Audience (RLSA and in-market): -90% to +900%, campaign or ad group level
- Demographics (age, gender, household income): -90% to +900%, campaign or ad group level
- Interactions (call extensions): -90% to +900%, campaign level
- Topics/Placements (Display): -90% to +900%, ad group level
- Content (Display): -90% to +900%, ad group level
The important caution with manual bid adjustments is that cumulative modifiers stack multiplicatively, not additively. If you have a +30% mobile adjustment and a +25% audience adjustment for remarketing lists, a mobile user on your remarketing list triggers a combined modifier of 1.30 x 1.25 = 1.625, or a 62.5% bid increase. This compounding effect is the most common source of unexplained cost spikes in manually managed campaigns, and it is extremely easy to miss if you are setting adjustments across multiple dimensions without calculating the combined ceiling.
How Should You Think About Device Bid Adjustments in 2026?
Device performance varies significantly by industry, conversion type, and funnel stage, and device bid adjustments remain the one modifier that carries real strategic weight even under automation. But the approach differs dramatically depending on your bid strategy.
Under Manual CPC or Enhanced CPC, device adjustments directly modify your bids. If desktop converts at a 5% rate and mobile at 2.8%, reducing mobile bids by -40% to -50% makes sense. Conversely, if your B2B lead gen campaign converts almost exclusively on desktop during business hours, you might set mobile to -100% and tablet to -70%.
Under Target CPA, device adjustments modify your CPA target, not your bids. This is the critical distinction. A +15% adjustment on mobile tells Google you are comfortable paying 15% more per mobile conversion. This makes sense when you know mobile leads have higher lifetime value or when mobile conversion tracking understates actual impact (common with phone call conversions or store visit attribution). A -30% adjustment on tablet tells Google to constrain tablet acquisition costs more aggressively.
Under Target ROAS, Maximize Conversions, or Maximize Conversion Value, device bid adjustments are fully ignored. The only functional device adjustment is -100%, which excludes the device entirely.
The broader strategic question is whether you should be adjusting for device at all or letting the algorithm handle it. The honest answer depends on the quality and completeness of your conversion data. If your conversion tracking captures the full picture, including phone calls, store visits, and cross-device conversions, Smart Bidding will optimize device allocation better than you can. If your tracking has blind spots (and most accounts have at least some), device adjustments on Target CPA campaigns provide a meaningful lever to compensate for what the algorithm cannot see.
What Has Changed About Location Bid Adjustments?
Location bid adjustments let you increase or decrease bids for specific geographic targets at the campaign level, with a range of -90% to +900%. For campaigns on Manual CPC, they function as direct bid modifiers. For Smart Bidding campaigns, they are ignored.
The subtlety that experienced managers know, but is rarely discussed in beginner resources, involves how Google handles overlapping geographic targets. If you set location targets for both “Florida” and “Orlando” with separate bid adjustments, Google does not combine them. Traffic from users in Orlando gets the Orlando adjustment, not a stacked Florida + Orlando modifier. This is different from how audience and device adjustments combine, and the inconsistency causes confusion when managers build complex geographic targeting structures.
The more strategic consideration for advanced campaign managers is whether location bid adjustments are the right tool at all, or whether campaign segmentation by geography produces better results. Splitting high-performing and low-performing regions into separate campaigns gives you independent budget control, independent bid strategy settings, independent ad copy, and clean performance data that is not muddied by overlapping modifiers. The tradeoff is management complexity. An account with 6 campaigns becomes 18 when you split by geography, and each campaign needs sufficient conversion volume to fuel Smart Bidding effectively.
The right answer depends on the specific account, which is part of why paid media management consistently resists one-size-fits-all frameworks.
How Do Audience Bid Adjustments Interact with Smart Bidding?
Under Manual CPC, audience bid adjustments are a powerful optimization tool. Adding remarketing lists, in-market audiences, customer match lists, or similar audiences to campaigns (or ad groups) with the “Observation” setting, and then applying bid adjustments, lets you bid more aggressively for users who are statistically more likely to convert without narrowing your targeting.
A +25% bid adjustment for your 30-day site visitor remarketing list tells Google to bid 25% higher when someone on that list searches for your keywords. This is one of the most effective manual bidding tactics in the platform because it layers behavioral intent data on top of keyword intent data.
Under Smart Bidding, audience bid adjustments are not supported. The algorithm already factors audience signals, including remarketing list membership, customer match status, in-market segment membership, and demographic profile, into every auction-time bid decision. Adding manual audience modifiers on top of Smart Bidding is redundant at best and creates conflicting signals at worst.
The important nuance is that adding audiences in “Observation” mode to Smart Bidding campaigns is still valuable, not for bid adjustment purposes, but for reporting. Observation-mode audiences give you performance segmentation data (conversion rates, CPA, ROAS by audience) without affecting how the algorithm bids. This data is essential for understanding which audiences drive the best performance and for informing broader marketing strategy decisions, even if you are not using the bid adjustment column.
The layered complexity of audience strategy, which audiences to observe, which to target, how to build customer match segments that actually improve algorithmic performance, and how to interpret cross-audience attribution, is one of the areas where the gap between a competent in-house manager and an experienced agency team becomes most apparent. The platform gives you the tools. Knowing which combinations actually move the needle requires pattern recognition across dozens of accounts and millions of dollars in managed spend.
What Are Seasonality Bid Adjustments, and Why Do Most Managers Miscalibrate Them?
Seasonality bid adjustments are an advanced tool within Google Ads that lets you inform Smart Bidding of expected changes in conversion rates during short, defined events. They are available for Search, Shopping, Display, and Performance Max campaigns using Target CPA, Target ROAS, or other Smart Bidding strategies. You access them through Tools and Settings > Shared Library > Bid Strategies > Advanced Controls.
Google’s own documentation emphasizes that Smart Bidding already accounts for predictable seasonal patterns. Seasonality adjustments are designed only for significant, short-duration events where conversion behavior will deviate dramatically from recent trends: a flash sale, a product launch, a holiday promotional weekend. They are ideal for events lasting 1 to 7 days. Google explicitly states they may not work well for events extending beyond 14 days.
Here is where most campaign managers make the critical miscalibration error. The adjustment input asks for an expected conversion rate change. If you ran a Black Friday promotion last year and saw a 100% increase in conversion rates, the intuitive move is to set a +100% seasonality adjustment. But as practitioners at SavvyRevenue documented, the adjustment operates more directly on bids than the interface suggests. A 100% seasonality adjustment typically produces something close to a 100% increase in CPCs, which may not be what you want at all.
The correct approach is to analyze how much your CPCs need to increase to capture the incremental demand, not how much your conversion rate changes. If conversion rates historically double during your sale event but CPCs only need to increase 25% to 30% to win the additional impressions, a +25% to +30% adjustment is far more appropriate than +100%. Getting this wrong means blowing through budget before mid-morning on the first day of a promotion. One large retailer famously discovered this the hard way during Black Friday 2019, when an oversized seasonality adjustment drained the daily budget by 11 AM.
There are also important guardrails to understand. Data collected during a seasonality adjustment period is not fully excluded from Smart Bidding’s learning. Google’s algorithm recognizes that the elevated conversion rate was temporary and does not let it skew long-term bid optimization. But the ramp-down period after the event can still produce inefficiency as the algorithm recalibrates. For multi-day sales events with gradual ramp-up and ramp-down, splitting the adjustment into multiple shorter periods with different modifiers produces more controlled results than a single flat adjustment across the full duration.
What Are Data Exclusions, and When Should You Use Them?
Data exclusions are the complementary tool to seasonality adjustments, also found under Advanced Controls. They instruct Smart Bidding to completely disregard conversion data from a specified time period. This is critical for maintaining bid accuracy after tracking disruptions.
The most common scenarios include accidental removal of conversion tracking code during a website update, a period where a conversion pixel was double-firing (inflating conversion counts), server outages that prevented form submissions from being recorded, or tag manager configuration changes that temporarily broke conversion attribution.
Without a data exclusion in place, the algorithm absorbs the corrupted data and adjusts bids based on inaccurate conversion signals. If conversion tracking was broken for three days and no conversions were recorded, Smart Bidding interprets this as a dramatic decline in conversion rate and aggressively reduces bids. When tracking is restored, it can take days or weeks for the algorithm to recover. Applying a data exclusion for the affected period tells the algorithm to ignore those days entirely, preserving the integrity of your bid optimization.
Google’s own documentation warns that data exclusions should be used sparingly and for genuine tracking issues, not as a routine optimization tactic. Overusing them can destabilize Smart Bidding’s learning model. They also recommend accounting for your account’s typical conversion delay when setting the exclusion window. If your account has a 7-day conversion delay, the exclusion window should extend 7 days beyond the tracking issue to capture the full impact.
This is one of those tools that sits untouched in 90% of Google Ads accounts, yet it can prevent thousands of dollars in wasted spend when a tracking issue occurs. Knowing it exists, understanding when to deploy it, and acting quickly when tracking breaks are the kinds of operational expertise markers that separate reactive account management from proactive strategic oversight.
How Does the Shift to AI Max and Performance Max Affect Bid Adjustment Strategy?
The trajectory of Google Ads is unmistakably toward more automation and less manual control. The introduction of AI Max for Search in 2025, the continued expansion of Performance Max, and the deprecation of Enhanced CPC and call-only ads all point in the same direction: Google wants advertisers focusing on strategy inputs (audiences, creatives, conversion data quality, budget allocation) rather than tactical bid management.
Performance Max campaigns received significant transparency upgrades in 2025, including channel-level reporting, full search term reporting for Search and Shopping placements, campaign-level negative keywords (up to 10,000), and demographic and device targeting controls. But bid adjustments within PMax remain extremely limited. The algorithm controls bidding entirely, using your target CPA or ROAS as the guardrail.
AI Max for Search goes further. Introduced as part of Google’s “Power Pack” framework alongside Performance Max and Demand Gen, AI Max enables automatic text customization, URL expansion, and Smart Bidding Exploration, a feature that temporarily relaxes your ROAS or CPA target to explore new traffic segments. Google reports that campaigns using AI Max with Smart Bidding Exploration saw an 18% increase in unique search query categories with conversions and a 19% increase in overall conversions.
For bid adjustment strategy, the implication is clear: the window for manual bid optimization is narrowing. The adjustment types that remain functional are device exclusions (-100%), Target CPA device modifiers, seasonality adjustments, and data exclusions. Everything else is being absorbed into the algorithm.
This does not mean campaign managers are becoming irrelevant. It means the skill set is evolving. The campaign managers who drive the best results in 2026 are the ones who understand conversion data architecture (which conversions to optimize for, how to weight them, when to use offline conversion imports), first-party data strategy (customer match segmentation, value-based bidding inputs), creative strategy (which asset combinations drive performance across surfaces), and budget allocation (when to consolidate, when to segment, how to use portfolio bid strategies to share learning across campaigns).
These are strategic capabilities that require deep platform expertise and cross-account pattern recognition. They are also the capabilities where an experienced agency partner compounds value most efficiently, because no single in-house manager sees the breadth of account structures, industry benchmarks, and algorithmic behavior patterns that a team managing dozens of accounts encounters daily.
What Bid Adjustment Mistakes Cost the Most Money?
Bid adjustment errors are rarely catastrophic on day one. They are quiet, persistent drains on efficiency that compound over weeks and months. Here are the patterns that account for the most wasted spend across the accounts we audit.
Stacking multiplicative adjustments without calculating the ceiling. A campaign with +30% mobile, +25% remarketing audience, and +20% ad schedule during peak hours creates a combined modifier of 1.30 x 1.25 x 1.20 = 1.95 for a mobile remarketing user searching during business hours. That is nearly double the base bid. Most managers set each adjustment independently based on segment-level performance data without calculating the combined exposure across overlapping segments. For accounts spending $50,000 or more per month, this compounding effect can add five figures in unnecessary cost annually.
Applying manual adjustments to Smart Bidding campaigns and assuming they are working. This is arguably the most common mistake. The adjustments sit in the interface looking active. The manager believes they are influencing bid behavior. They are not. Meanwhile, the campaign is missing optimization opportunities because the manager is investing time in adjustments that have no effect instead of working on conversion data quality, audience strategy, or creative testing, the inputs that actually influence Smart Bidding performance.
Oversizing seasonality adjustments based on conversion rate changes rather than CPC requirements. We covered this in detail above, but it bears repeating because the financial impact is immediate and significant. An oversized adjustment during a promotional event does not just overpay for clicks. It accelerates budget consumption, which means missing late-day demand entirely.
Ignoring data exclusion opportunities after tracking disruptions. Every day of corrupted conversion data that Smart Bidding absorbs creates a compounding optimization error. A three-day tracking outage without a data exclusion can depress bid accuracy for two weeks or more as the algorithm processes the false signal and gradually recalibrates.
Using bid adjustments as a substitute for campaign architecture. If you find yourself applying heavy location adjustments (-80% on some regions, +200% on others) within a single campaign, the adjustment layer is doing work that campaign segmentation should be handling. Heavy adjustments create management complexity, reduce data clarity, and make optimization harder. Splitting into separate campaigns by geography (or audience, or device) gives you cleaner data, independent budgets, and faster learning for Smart Bidding.
What Does an Optimized Bid Adjustment Strategy Look Like in 2026?
The sophisticated approach to bid adjustments in 2026 is less about the adjustments themselves and more about understanding the full ecosystem of bidding controls and knowing which tool to deploy for which purpose.
For Smart Bidding campaigns, your bid adjustment toolkit is effectively limited to device exclusions (-100%), device CPA modifiers (Target CPA only), seasonality adjustments, and data exclusions. Focus your optimization energy on the inputs that actually influence the algorithm: conversion tracking accuracy, first-party data quality, campaign structure, creative asset variety, and target CPA/ROAS calibration. These are the levers that move performance.
For Manual CPC campaigns, bid adjustments remain fully functional across all eight types. Use them strategically based on actual performance data (not assumptions), calculate combined modifier ceilings before setting overlapping adjustments, and set adjustments at the campaign level where data volume supports statistical significance. Move to ad group-level adjustments only when campaign-level data shows significant internal variation.
For portfolio bid strategies, consider using portfolio-level target settings across multiple campaigns to give the algorithm more data and more flexibility to allocate budget efficiently. Google reports that portfolio strategy adoption has grown significantly, with typical performance improvements of 19% to 27% in overall account ROAS compared to campaign-level strategies.
For all campaigns, maintain a calendar of expected promotional events and prepare seasonality adjustments in advance, calibrated to expected CPC increases (not conversion rate increases). Establish a data exclusion protocol so your team can act within hours of a tracking disruption. And review your bid adjustment settings quarterly to clear out legacy modifiers that no longer reflect current performance patterns.
Frequently Asked Questions
Do bid adjustments work with Smart Bidding in Google Ads?
Most bid adjustments are ignored by Smart Bidding strategies including Target CPA, Target ROAS, Maximize Conversions, and Maximize Conversion Value. The two exceptions are a -100% device exclusion (which works across all automated strategies) and device bid adjustments on Target CPA campaigns, which modify the CPA target rather than the bid itself. All other adjustment types, including location, demographics, audience, and ad schedule, are not applied under Smart Bidding because the algorithm already factors those signals into every auction-time bid decision.
What is the difference between a seasonality bid adjustment and a regular bid adjustment?
Regular bid adjustments are persistent percentage modifiers applied to specific segments (device, location, audience, time of day) that remain in effect until changed. Seasonality bid adjustments are temporary, event-based adjustments that inform Smart Bidding of expected conversion rate changes during short events like sales or promotions. They are designed for 1 to 7 day windows, operate through the Advanced Controls section of Bid Strategies, and automatically revert after the scheduled period ends. Unlike regular adjustments, seasonality adjustments are specifically designed to work with Smart Bidding.
How do I set the right seasonality bid adjustment percentage?
Calibrate seasonality adjustments based on expected CPC increases, not conversion rate increases. If your conversion rate typically doubles during a promotional event but you only need 25% to 30% higher CPCs to capture the incremental demand, set the adjustment at +25% to +30%. Setting it at +100% (matching the conversion rate change) will typically produce roughly a 100% CPC increase, which can deplete daily budgets in hours. Analyze historical CPC and impression share data from equivalent past events to determine the appropriate modifier. For multi-day promotions with uneven demand, consider splitting the adjustment into shorter periods with different modifiers.
When should I use data exclusions in Google Ads?
Use data exclusions when your conversion tracking has been disrupted, corrupted, or misconfigured during a specific time period. Common scenarios include accidental removal of conversion tracking code during website updates, double-firing conversion pixels, server outages preventing form submissions, and tag manager misconfigurations. Apply the exclusion promptly after identifying the issue, and extend the exclusion window to account for your account’s typical conversion delay. Data exclusions are not meant for routine optimization. They are an emergency tool for protecting Smart Bidding from learning on inaccurate data.
Are bid adjustments becoming obsolete?
Bid adjustments are not disappearing, but their role is fundamentally changing. As Google Ads moves toward greater automation through AI Max, Performance Max, and enhanced Smart Bidding features, the scope of manual bid adjustment influence is narrowing. Device exclusions, seasonality adjustments, and data exclusions remain important strategic tools. But the granular, segment-by-segment bid modifier approach that defined PPC management five years ago is being replaced by a model where campaign managers focus on strategic inputs (conversion data quality, audience signals, creative assets, budget allocation) and the algorithm handles auction-time bid decisions.
Should I use Manual CPC or Smart Bidding in 2026?
Manual CPC makes sense for brand keyword campaigns requiring predictable cost control, new campaigns with zero conversion history, and diagnostic or testing scenarios. Once a campaign reaches 30 or more conversions per month (50 or more for Target ROAS), Smart Bidding consistently outperforms manual bidding because it processes thousands of contextual signals per auction that human managers cannot evaluate in real time. The transition should be phased: start with Maximize Conversions to build conversion data, then layer in a Target CPA or Target ROAS once you have baseline cost-per-conversion data. Avoid setting unrealistic targets during the learning period, as this constrains the algorithm and degrades performance.
Bid Adjustments Are a Precision Tool, Not a Set-and-Forget Solution
The Google Ads landscape in 2026 rewards campaign managers who understand the platform deeply enough to know which levers actually produce results and which ones create a false sense of control. Bid adjustments were once the centerpiece of PPC optimization. Today, they are one component within a far more complex ecosystem of automated bidding, audience strategy, creative optimization, and conversion data architecture.
The managers and agencies producing the strongest results are not the ones with the most granular bid adjustments. They are the ones with the cleanest conversion data, the most thoughtful campaign structures, the best first-party data integration, and the strategic judgment to know when to guide the algorithm and when to let it work.
That combination of technical depth, strategic perspective, and cross-account pattern recognition is exactly what Bigeye brings to paid media management. We don’t just set bid adjustments and monitor dashboards. We build the data infrastructure, audience architecture, and measurement frameworks that make every dollar in your Google Ads account work harder.
If your campaigns are sophisticated enough that you are reading an article about bid adjustment strategy, they are sophisticated enough to benefit from an agency partner that manages at this level every day. Let’s talk about what your account could be doing.
