A setting in paid search campaigns that increases or decreases a bid when certain conditions are met, such as device or location.
Advertisers managing paid search campaigns and concerned with ad placement in AI-generated search summaries.
01How bid adjustments work
Bid adjustments are percentage changes applied to your base cost-per-click bid. For example, a +20% mobile adjustment means you bid 20% more when a search comes from a smartphone. The adjusted bid is used in the ad auction to determine ad rank. In AI search, ads can appear in overviews, chat responses, or answer boxes. A higher bid from an adjustment can improve your ad's chance of being selected for those placements, especially when the AI model considers ad relevance alongside organic results. Adjustments can be set for device (mobile, tablet, desktop), location (country, city, radius), time of day, day of week, audience lists, and more. Each adjustment multiplies the base bid, so multiple active adjustments compound. The final bid is what competes in the auction. Google's ad rank formula uses this bid, quality score, and ad extensions to decide which ads show and in what order. In AI search, the same auction principles apply, though the exact weight of bid versus relevance may differ for generative placements.
Bid adjustments let you pay more or less for an ad depending on who is searching, where they are, or what device they use.
02What to do about bid adjustments
Start by auditing your current bid adjustments across campaigns. Identify which devices, locations, or times drive the most AI search traffic for your brand. Use analytics to see where AI search results (like Google AI Overviews or Bing Chat) are generating impressions or clicks. Then set bid adjustments that align with those patterns. For example, if mobile users see AI overviews more often, increase your mobile bid adjustment by 10-20%. Test one adjustment at a time and measure changes in brand appearance metrics. Use campaign experiments to isolate the effect. Also consider negative adjustments for low-performing segments, such as -50% for desktop if AI search rarely shows ads there. Document your baseline before making changes. Review adjustments quarterly because AI search behavior evolves as models update. Coordinate with your organic SEO team to ensure paid and organic efforts reinforce each other in AI search surfaces.
03How bid adjustments are measured
The primary metric is impression share, both overall and segmented by the adjustment condition (e.g., mobile impression share). Compare impression share before and after applying an adjustment. Also track click-through rate and cost per acquisition to ensure the adjustment doesn't inflate costs without returns. For AI search specifically, measure brand appearance rate: the percentage of AI-generated search responses that include your brand. This can be tracked using your product's brand appearance measurement tool. Look at changes in that rate for queries where you applied adjustments. A successful bid adjustment should increase brand appearance in AI search without a disproportionate rise in cost. Monitor quality score as well; extreme adjustments can lower it if they lead to irrelevant placements. Use segment reports in your ad platform to isolate performance by device, location, or time.
04Common mistakes
- Setting extreme adjustments (e.g., +300%) without historical data, which can waste budget and lower quality score.
- Ignoring mobile vs desktop differences in AI search behavior — mobile often triggers different AI response formats.
- Applying the same adjustment to all campaigns without segmenting by goal or audience.
- Not accounting for time-of-day when AI search usage peaks, leading to missed opportunities or overspend.
- Forgetting to pause adjustments during testing phases, causing conflicting signals in the auction.
05Limits of bid adjustments
Bid adjustments only affect paid placements. They cannot force your brand to appear in organic AI search results. If your brand is not cited organically, an ad adjustment may still get your ad into an AI overview, but the brand mention will be marked as sponsored. Adjustments are also constrained by your daily budget and quality score; a low quality score can prevent your ad from showing even with a high adjustment. Bid adjustments are often confused with bid modifiers — they are the same thing, but different platforms may call them 'bid adjustments' or 'bid modifiers'. Not all AI search surfaces support ads yet; for example, some chatbot responses do not include sponsored content. In those cases, bid adjustments have no effect. Finally, adjustments compound, so using many at once can produce unintended bid amounts.
06Worked example
A travel brand noticed its ads appeared less often in Google AI Overviews on mobile. It increased its mobile bid adjustment from 0% to +25%. Over two weeks, mobile impression share rose 15% and brand mentions in AI search increased by 10%. The cost per acquisition stayed flat because the extra clicks converted well. The brand then added a +10% adjustment for the time window 6-9 PM when AI search usage spiked, further improving visibility.
Frequently asked questions
How is a bid adjustment different from a bid modifier?
They are essentially the same thing. Different platforms use different names, but both refer to a percentage change applied to your base bid when a specific condition is met. The key is to understand the condition, not the label.
Should I use bid adjustments to improve how my brand appears in AI search summaries?
It depends on whether the AI summary draws from paid placements. If your ads appear in the summary, bid adjustments can help you show up more often for certain conditions. However, if the summary is purely organic, bid adjustments won't directly affect it.
How do I set up a bid adjustment for mobile devices?
In your campaign settings, look for the device adjustment section and apply a positive or negative percentage for mobile. For example, a +20% adjustment increases your bid by 20% when a user is on a mobile device. The change takes effect within hours.
Do bid adjustments still matter if AI search summaries are organic?
They matter for the paid placements that may accompany or influence those summaries. Even if the summary itself is organic, a strong paid presence can increase brand visibility and click-through rates. So bid adjustments remain relevant for overall brand appearance.
What happens if I set a bid adjustment too high?
You risk overspending on clicks that don't convert, which reduces your return on investment. You might also exhaust your daily budget quickly, causing your ads to stop showing later. Monitor impression share and cost per conversion to catch this early.
How quickly do bid adjustments take effect?
Typically within a few hours, but full data on performance may take a day to accumulate. You can check impression share segmented by the adjustment condition after 24 hours to see the impact. Adjust further if needed based on that data.
Asked out loud
spoken, not typedThe same term in the words somebody uses speaking to an assistant rather than typing into a box — written from the situation, which is why each one carries the situation it came from.
You should apply a mobile bid adjustment. In your campaign settings, set a positive percentage for mobile devices. This will automatically increase your bids when a user is on a phone.
It sounds like you need to check your location bid adjustments. You can set a higher bid for specific geographic areas to improve ad visibility there. Review your campaign's location settings.
You can use a day-of-week bid adjustment. Set a positive adjustment for weekends to increase your bids on those days. This is a quick fix without changing your entire campaign structure.