How much budget does a typical Google Ads account waste without a negative keyword strategy?

Independent estimates commonly cite 20-40% of spend going to irrelevant search queries in accounts without an actively maintained negative keyword list — a range that has reportedly climbed as Google's matching (particularly broad match and AI Max) has broadened.

How often should negative keyword lists be reviewed?

Weekly for an active campaign, at minimum during the first month of any new campaign or bidding change — search term reports should be checked frequently enough that an irrelevant query pattern doesn't have weeks to burn budget before being caught.

Should negative keyword lists be shared across campaigns or built individually?

A shared list for universally irrelevant terms (competitor brand names you don't want, clearly unrelated categories, common false-positive patterns) saves duplicate work across campaigns, while campaign-specific negatives handle terms only irrelevant to that particular campaign's specific offer.

GUIDES · CORNERSTONE

Negative Keywords: The Complete Strategy Guide

Q: Can Performance Max campaigns use negative keywords?

Yes, at the campaign level — Google increased the Performance Max negative keyword limit from 100 to 10,000 slots in March 2025 and added shared negative keyword list support across PMax campaigns in August 2025, a major improvement over PMax's original, very limited negative keyword capability.

The average account reportedly wastes 20-40% of spend on irrelevant queries. The fix isn't complicated — it's just the one maintenance task most accounts quietly stop doing after the first month.

Rohan Alexander · 11 min read · Updated July 2026

Negative Keywords: The Complete Strategy Guide — key topics (Google Ads Academy guide by Zephra)

Where this sits: Stage 2 (Keyword Strategy) of the Google Ads Operating System — the defense layer underneath AI Max for Search's expanded matching and Performance Max's broad automation.

On this page Quick answer The 20-40% waste problem Negative match types Negative keywords in Performance Max specifically Shared lists vs campaign-specific negatives Common negative keyword categories to build first The weekly search term review process When a negative keyword strategy goes too far Variations by campaign type Case study Decision matrix Common mistakes Troubleshooting Checklist AI prompts FAQ How Zephra helps

Quick Answer

Independent estimates put typical wasted spend on irrelevant queries at 20-40% for accounts without an actively maintained negative keyword strategy — a range that's reportedly grown as Google's own matching (broad match, AI Max) has broadened. The fix is a weekly search term review, a shared negative list for universally irrelevant terms, and campaign-specific negatives for anything narrower. Performance Max's negative keyword limit jumped from 100 to 10,000 slots per campaign in March 2025, making this genuinely actionable there too, not just on Search.

The 20-40% Waste Problem

Independent reporting on Google Ads accounts consistently finds a substantial share of spend — commonly cited in the 20-40% range — going to search queries that technically triggered an ad but had no real commercial relevance to what's being sold. This isn't a one-time setup gap; it's a maintenance gap. Google's own matching has grown more aggressive over time (broad match expansion, AI Max's query broadening), meaning a negative list that was comprehensive a year ago is very likely stale today without ongoing additions.

Negative Match Types

Type	Behavior	Use for
Negative broad match	Blocks the query if all terms appear, any order	Broad, obviously irrelevant term combinations
Negative phrase match	Blocks queries containing the exact phrase in order	A specific irrelevant phrase pattern
Negative exact match	Blocks only the exact query	A specific, precisely-identified irrelevant search

Negative broad match is the most common starting point since it catches the widest range of variations with the least ongoing maintenance, but it also carries the highest risk of accidentally blocking a genuinely relevant query that happens to share the same words — review broad negatives more cautiously than phrase or exact negatives.

Negative Keywords in Performance Max Specifically

Performance Max originally shipped with only 100 negative keyword slots per campaign — a serious limitation for a campaign type spanning search, shopping, display, YouTube, Gmail, and Discover simultaneously, and advertisers reported up to 40% of PMax spend going to irrelevant queries they simply couldn't block. Google increased this to 10,000 slots per campaign in March 2025, and added shared negative keyword list support across PMax campaigns in August 2025 — both genuinely significant improvements. That said, 10,000 slots means little without a process for identifying which terms actually need blocking; PMax's limited query-level transparency (compared to standard Search or AI Max) makes this harder than it is for Search campaigns, since you can't always see exactly which query triggered a given impression.

Shared Lists vs Campaign-Specific Negatives

A shared negative keyword list — applied across every relevant campaign at once — is the efficient home for universally irrelevant terms: competitor brand names you don't want to appear for, obviously unrelated categories, common junk-query patterns (job seekers, free/DIY searches for a paid service). Campaign-specific negatives handle terms that are only irrelevant to one particular campaign's specific offer, which a shared list would apply too broadly. Building both — a strong shared foundation plus targeted campaign-level additions — avoids duplicating the same universal negatives across every campaign individually.

Common Negative Keyword Categories to Build First

Category	Example terms to consider
Job-seeker intent	"jobs," "careers," "salary," "hiring"
Free/DIY intent (for a paid service)	"free," "diy," "how to do it yourself"
Unrelated but overlapping categories	Terms that share words with your offer but describe something genuinely different
Competitor brand terms	Depending on strategy — some advertisers deliberately bid on these, others exclude them
Research/informational intent	"what is," "definition," "meaning of" for a bottom-funnel, purchase-intent campaign

The Weekly Search Term Review Process

Pull the search terms report for each active campaign, sorted by spend.
Scan the highest-spend queries first — this is where waste concentrates and where a single negative addition has the most impact.
Add negatives at the appropriate match type and list level (shared vs campaign-specific) per the guidance above.
Note any pattern, not just individual terms — if several queries share a theme, a single well-chosen negative broad match term may cover future variations too.

This weekly review is exactly the task most accounts do diligently for the first month and then quietly let slip. Zephra's Feed Agent runs this review continuously, adding negatives the moment a wasteful query pattern appears rather than waiting for the next scheduled check. See what it would catch in your account, free.

When a Negative Keyword Strategy Goes Too Far

Overly aggressive negative broad match terms can accidentally exclude genuinely relevant queries that happen to share words with an irrelevant pattern — a broad negative meant to block "free" searches could inadvertently block a query like "free consultation," which might be exactly the offer being advertised. Review broad match negatives against the account's actual offers before adding them, and periodically audit existing negatives for any that may be excluding more than intended as the offer or product line evolves.

Variations by Campaign Type

Campaign type	Negative keyword approach
Standard Search	Full query transparency makes this the easiest campaign type to maintain negatives for
AI Max for Search	Same transparency as standard Search, but expansion rate demands more frequent review
Performance Max	Campaign-level only, limited query visibility — rely more on category-level and pattern-based negatives

Case Study

An ecommerce account running Performance Max noticed cost per purchase climbing over several months with no obvious cause in the standard reporting. A manual audit of the limited query insights available, cross-referenced against the site's own analytics for entry pages with poor conversion rates, revealed a recurring pattern of job-seeker and informational-intent traffic reaching the site through PMax. Building a shared negative list targeting these specific patterns and applying it across all PMax campaigns reduced wasted spend meaningfully within the following month, improving blended cost per purchase without any change to bids, budget, or creative.

Decision Matrix

Situation	Priority
No negative keyword review has happened since initial setup	Run a full search term audit before any other optimization
Running Performance Max with rising CPA and no clear cause	Build shared negatives targeting common junk-query categories
A broad negative may be excluding relevant traffic	Review it against current offers and narrow the match type if needed

Common Mistakes

Setting up negative keywords once at launch and never reviewing them again.
Using only campaign-specific negatives, duplicating the same universal terms across every campaign.
Adding overly broad negative match terms that accidentally exclude relevant queries.
Assuming Performance Max's negative keyword limitations haven't changed since the campaign type launched.

Troubleshooting

Rising CPA with no obvious cause: run a search term audit (or, for PMax, cross-reference site analytics for poor-converting entry pages) before assuming it's a bidding or creative issue.

A negative keyword seems to be blocking relevant traffic: check the match type — broad negatives are the most likely culprit and may need narrowing to phrase or exact.

Checklist

☐ A shared negative list exists for universally irrelevant terms
☐ Campaign-specific negatives added for narrower, offer-specific exclusions
☐ Search term reports reviewed weekly, not just at launch
☐ Performance Max campaigns have negatives configured, using the full 10,000-slot limit where relevant
☐ Broad match negatives periodically reviewed for unintended over-exclusion

AI Prompts to Speed This Up

"Review this search term report [paste] and categorize which queries should become negative keywords, and at what match type."
"Suggest a starter shared negative keyword list for a [business type] that wants to exclude job-seeker and free/DIY intent."

FAQ

How much budget does a typical account waste without a negative keyword strategy?

Commonly cited estimates are 20-40% of spend on irrelevant queries.

Can Performance Max campaigns use negative keywords?

Yes, at the campaign level — up to 10,000 slots since March 2025, with shared list support added August 2025.

How often should negative lists be reviewed?

Weekly for active campaigns, more frequently during the first month of any new campaign or bidding change.

Should negatives be shared or campaign-specific?

Both — a shared list for universal terms, campaign-specific negatives for narrower exclusions.

HOW ZEPHRA HELPS

The 20-40% waste problem is really a maintenance problem. Zephra never stops maintaining it.

Zephra reviews search term reports continuously across Search, AI Max, and Performance Max, adding negatives the moment a wasteful pattern appears — not once a month, and not only when someone remembers to check.

Start Free Audit →

Sources & Further Reading

Google Ads Help — About Negative Keywords — Official documentation on negative keyword behavior and limits across campaign types.
WordStream — 2026 Google Ads Benchmarks Report — Current cross-industry CPC, CTR, and conversion rate benchmarks.

Waste percentage estimates cited in this guide come from independent advertiser analysis, not an official Google figure — actual waste varies significantly by account and industry.