Where Your Google Ads Budget Is Leaking (and How to Plug It)

The average Google Ads account wastes 20–40% of its budget on clicks that will never convert. At $30K/month in ad spend, that’s $6,000–$12,000 per month going straight into Google’s pocket with nothing to show for it.

The good news: most wasted spend comes from a handful of fixable problems.

1. Missing negative keywords

How much it costs you: 10–25% of total spend in a typical account.

Every search campaign matches to queries you didn’t intend. Without negative keywords, you’re paying for:

• Informational searches: “what is [your product category],” “how does [your solution] work” — people researching, not buying
• Job searches: “[your industry] jobs,” “[your product] salary”
• Free/cheap seekers: “free [your product],” “cheap [your category]”
• Irrelevant modifiers: “[your product] login,” “[your product] support,” “[competitor] careers”

How to fix it: Pull your search terms report weekly. For the first month, you’ll find dozens of irrelevant terms per week. After 2–3 months of consistent management, the flow slows to a trickle. Build a shared negative keyword list and apply it across all campaigns.

Pro tip: Create pre-built negative keyword lists for common waste categories (jobs, free, DIY, reviews, careers, login, support) and apply them at account level on day one.

2. Wrong match types with wrong bidding

How much it costs you: 5–15% of total spend.

Broad match keywords without Smart Bidding is the single most expensive mistake in Google Ads. Broad match tells Google to show your ad for anything related to your keyword — and Google interprets “related” very generously.

“project management software” on broad match might trigger ads for “how to manage my personal projects,” “free to-do list app,” or “project manager job openings.”

How to fix it:

• If you’re using broad match, pair it with Target CPA or Target ROAS bidding. Smart Bidding constrains broad match by only competing for auctions likely to convert
• If you’re using Manual CPC, switch to phrase or exact match
• Review your search terms report specifically for broad match keywords — sort by spend and look for irrelevant queries

3. No geographic targeting refinements

How much it costs you: 5–15% of total spend, depending on your market.

If you serve the US market, you’re probably targeting “United States.” But not all geography performs equally:

• Some states or cities have dramatically higher CPCs with lower conversion rates
• You may be paying for clicks from regions where you can’t actually serve customers
• Google’s default location setting is “People in, or who show interest in, your targeted locations” — which means someone in another country researching your market might see your ad

How to fix it:

• Go to Locations in your campaign settings and switch from “Presence or interest” to “Presence” only
• Pull a geographic report for the last 90 days. Sort by cost. Identify regions with high spend and no conversions. Exclude them
• For local businesses: tighten your radius. A 50-mile radius wastes money on clicks from people who will never drive to your location

4. All-day, every-day ad scheduling

How much it costs you: 5–10% of total spend for B2B; less for ecommerce.

If you’re a B2B company running ads at 2 AM on Saturday, you’re paying for clicks from people who will never fill out a contact form or book a demo. Your office is closed. Your sales team is sleeping.

Even for ecommerce, there are usually hours and days with dramatically lower conversion rates.

How to fix it:

• Pull an hourly performance report for the last 90 days. Look for hours with high spend and low/zero conversions
• For B2B: run ads during business hours (7 AM – 8 PM) in your target time zones on weekdays. Test weekends at reduced budgets
• For ecommerce: use bid adjustments to reduce spend during historically low-performing hours
• Don’t pause ads entirely during off-hours — set bid adjustments of -50% to -80% instead. This lets you capture high-intent off-hours traffic at lower CPCs

5. Ignoring device performance differences

How much it costs you: 5–10% of total spend.

In many B2B accounts, mobile traffic converts at one-third the rate of desktop. In some ecommerce accounts, the opposite is true. Yet most advertisers let Google allocate budget evenly across devices.

How to fix it:

• Pull a device performance report for the last 90 days
• Compare conversion rates and CPA across mobile, desktop, and tablet
• If mobile CPA is 2x+ desktop CPA, apply a -30% to -50% bid adjustment on mobile
• Better yet, fix your mobile landing page. If mobile conversion rates are low, the problem is usually a slow, poorly formatted mobile experience — not mobile users themselves
• For lead gen: check mobile lead quality. Sometimes mobile converts at a lower rate but the leads that do convert are equally valuable

6. Paying for existing customers

How much it costs you: 2–5% of total spend, sometimes much more for branded campaigns.

If you’re running branded search campaigns (and you should be), you’re paying every time an existing customer clicks your ad to log in, find your support page, or navigate to your site.

For non-branded campaigns, existing customers searching for your product category might click your ad instead of going directly to your site.

How to fix it:

• Upload your customer email list as an audience in Google Ads
• Apply this audience as an exclusion to your campaigns (or at minimum, set a -100% bid adjustment)
• For SaaS: exclude users who have visited your login page or dashboard in the last 30 days
• Review your branded campaign search terms for navigation queries (“[your product] login,” “[your product] pricing page”) and add them as negatives or create separate, low-bid campaigns for them

Quantifying your waste

Here’s a quick exercise to estimate your wasted spend:

1. Search terms report: What percentage of your spend goes to irrelevant queries? (Typically 10–20%)
2. Geographic report: What percentage of spend goes to regions with zero conversions? (Typically 5–10%)
3. Hourly report: What percentage of spend occurs during your zero-conversion hours? (Typically 5–10% for B2B)
4. Device report: What’s the CPA delta between your best and worst device? How much do you spend on the worst one? (Typically 5–10% waste)

Add those up. If the total is 20–40% of your monthly spend, you’re in the normal range. Which means you have a significant, concrete opportunity to improve performance without spending an additional dollar.

The compounding effect

Here’s what makes wasted spend so expensive: it compounds. Every dollar wasted on a bad click is a dollar you didn’t invest in a converting keyword. That means:

• Lower conversion volume, which means less data for Smart Bidding to learn from
• Lower Quality Scores from poor CTR on irrelevant queries, which raises CPCs on good queries
• Artificially inflated CPA, which may cause you to reduce budget on campaigns that would be profitable if the waste were eliminated

Cutting waste doesn’t just save money — it makes your entire account perform better.

At SemGuns, waste elimination is the first thing we do in every new account. Most clients see a 15–30% improvement in CPA within the first month just from plugging these leaks.

This is especially critical for startups operating on tight budgets — every wasted dollar significantly impacts runway and growth potential. If you’re running a startup, check out our complete Google Ads guide for startups for budget-conscious optimization strategies.

Book a 15-minute call to discuss your account.