Bid Adjustments are percentage-based modifiers in Google Ads that increase or decrease your bids for specific segments such as devices, locations, times of day, audiences, and demographics. They allow you to bid more aggressively for high-performing segments and conserve budget on underperforming ones without creating separate campaigns.
Key Takeaways
- Expressed as percentage modifiers from -100% to +900%
- Available for devices, locations, ad schedule, audiences, demographics, and interactions
- Fully functional with Manual CPC and Enhanced CPC
- Mostly ignored by Smart Bidding strategies (Target CPA, Target ROAS, Maximize Conversions) except -100% device exclusions
- Multiple adjustments can stack multiplicatively
What Are Bid Adjustments
Bid Adjustments let you modify your base bids for specific contexts without restructuring your campaigns. Instead of creating separate campaigns for mobile and desktop, you apply a +20% bid adjustment for mobile (or -30% if mobile underperforms).
| Adjustment Type | Range | Example |
|---|---|---|
| Device | -100% to +900% | Mobile: -20%, Tablet: -100% (exclude) |
| Location | -90% to +900% | New York: +15%, Rural areas: -30% |
| Ad Schedule | -90% to +900% | Weekdays 9AM-5PM: +10%, Midnight-6AM: -50% |
| Audiences | -90% to +900% | Remarketing list: +50%, In-market: +25% |
| Demographics | -90% to +900% | Age 25-34: +20%, Unknown: -10% |
| Interactions | -90% to +900% | Call interactions: +15% |
The -100% adjustment is special: it completely excludes that segment. A -100% device adjustment for tablets means your ads never show on tablets. No other percentage completely suppresses serving.
How It Works
Bid adjustments modify your base bid using percentage multiplication:
Single adjustment:
- Base bid: $5.00
- Mobile adjustment: +20%
- Final bid: $5.00 x 1.20 = $6.00
Multiple adjustments stack multiplicatively:
- Base bid: $5.00
- Mobile: +20%
- New York location: +15%
- Remarketing audience: +50%
- Final bid: $5.00 x 1.20 x 1.15 x 1.50 = $10.35
This stacking effect can produce bids significantly above your base bid. In the example above, a $5 base bid becomes $10.35 for a remarketing user on mobile in New York.
Compatibility with bidding strategies:
| Bidding Strategy | Bid Adjustments Respected? |
|---|---|
| Manual CPC | Yes — all adjustments applied |
| Enhanced CPC | Yes — adjustments applied, then ECPC modifies further |
| Target CPA | No — only -100% device exclusion |
| Target ROAS | No — only -100% device exclusion |
| Maximize Conversions | No — only -100% device exclusion |
| Target Impression Share | No — only -100% device exclusion |
This is critical: if you use Smart Bidding, your bid adjustments for location, schedule, and audience are ignored (the algorithm makes its own adjustments). The only exception is -100% on a device, which acts as an exclusion.
Practical Example
A plumbing company using Manual CPC analyzes performance by segment and sets adjustments:
Performance by device:
| Device | Clicks | Conv. Rate | CPA | Adjustment |
|---|---|---|---|---|
| Desktop | 400 | 5.0% | $60 | Baseline (0%) |
| Mobile | 800 | 7.5% | $40 | +25% |
| Tablet | 100 | 2.0% | $150 | -50% |
Performance by time of day:
| Time | Clicks | Conv. Rate | CPA | Adjustment |
|---|---|---|---|---|
| 6AM-9AM | 200 | 8.0% | $37.50 | +30% |
| 9AM-5PM | 600 | 5.5% | $54.55 | Baseline (0%) |
| 5PM-9PM | 400 | 6.0% | $50.00 | +10% |
| 9PM-6AM | 100 | 1.5% | $200.00 | -70% |
Performance by audience:
| Audience | Conv. Rate | CPA | Adjustment |
|---|---|---|---|
| New visitors | 4.0% | $75 | Baseline (0%) |
| Remarketing (visited site) | 12.0% | $25 | +75% |
| Similar audiences | 6.0% | $50 | +20% |
Combined effect for a high-value scenario:
- Base bid: $3.00
- Mobile user at 7 AM from remarketing list
- Final bid: $3.00 x 1.25 (mobile) x 1.30 (morning) x 1.75 (remarketing) = $8.53
This bid reflects the high value of a returning customer searching for a plumber on their phone during morning emergency hours — exactly the situation that warrants aggressive bidding.
Why It Matters
Bid adjustments provide granular control over budget allocation within campaigns:
- Segment optimization — rather than treating all clicks equally, adjustments let you bid proportionally to the value of each segment. Mobile converts better? Bid more. Late night wastes money? Bid less.
- Campaign structure simplification — without bid adjustments, you would need separate campaigns for each device, location, and time segment. Adjustments let you manage these variations within a single campaign.
- Testing and learning — bid adjustments let you test the impact of different segments without structural changes. Set an audience adjustment to +0% (observation mode) to collect data before deciding on a bid change.
- Quick response — when you notice a segment underperforming, a bid adjustment change takes effect immediately. Restructuring campaigns takes days.
The important caveat for modern Google Ads: as Smart Bidding adoption grows, manual bid adjustments become less relevant. Smart Bidding strategies already adjust for device, location, time, and audience signals in real time, typically with more granularity than manual adjustments can achieve. If you use Smart Bidding, focus your optimization efforts on campaign structure, creative, and audience signals rather than bid adjustments. Reserve manual bid adjustments for accounts using Manual CPC or Enhanced CPC.