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Why Is Google Ads Spending More Than My Daily Budget?

  • Marketingchimp
  • Jul 9
  • 3 min read

Updated: 3 days ago


You log into your Google Ads account expecting your campaign to be on track — but instead, it’s gone over your daily budget. Sometimes by a little. Sometimes by a lot. You’re left wondering: Did I do something wrong? Is Google just helping itself to my wallet?


Here’s the truth: Google can legally spend up to 2x your daily budget on any given day — and it’s not a glitch. It’s part of how the system is designed. But don’t panic. In this post, we’ll explain why it happens, when it’s normal, when it’s not, and how to stay in control.


The Short Answer


Yes, Google Ads can spend more than your daily budget, but it shouldn’t exceed your monthly limit (which is your daily budget × 30.4). Google calls this "overdelivery", and it’s technically allowed within that limit.


If your daily budget is £20:


  • On some days, you may spend £40

  • On other days, you might spend £10

  • But across the month, your spend should average out to £608 (£20 × 30.4)


This allows Google to take advantage of high-traffic days or times when more people are searching for your keywords — without missing out on opportunity.


Why Does Google Overspend Your Budget?


Here’s how Google justifies it:


  • To maximise performance on days when traffic is higher

  • To reach your campaign goals more efficiently

  • To account for daily fluctuations in search volume


Imagine you're running ads for a wedding photographer. Weekends or evenings may bring a spike in searches. Google may spend more on those days to take advantage of higher intent.


The 30.4-Day Rule: What It Means


Google uses 30.4 days as the average number of days in a month.


Formula:


Daily Budget × 30.4 = Max Monthly Spend

Example:


  • Daily budget: £15

  • Max monthly spend = £456


If you spend £25 one day and £5 the next, it’s not an issue as long as it stays under £456 for the month.


When It Becomes a Problem


Even though overdelivery is technically “within the rules,” sometimes spend really gets out of hand. Watch out for:


  • Campaigns using broad match keywords + Smart Bidding — this combo can spend fast

  • New campaigns with aggressive bidding and no data

  • No max CPA or target ROAS set — Google runs wild trying to “learn”


Also: If your campaigns are running across multiple time zones, budgets may overspend due to overlap — especially if you don’t use ad scheduling.


How to Stay in Control


Here are 5 ways to stop your campaigns from overspending beyond comfort:


1. Use Shared Budgets (If Running Multiple Campaigns)


  • Keeps spend balanced across campaigns

  • Especially useful if one campaign is cannibalising budget


2. Use Portfolio Bid Strategies with Limits


  • Set max CPCs or target CPA limits

  • Prevents Google from bidding recklessly high on key terms


3. Use Ad Scheduling


  • Only show ads during peak hours

  • Prevents random spikes at 3 AM


4. Pause Campaigns Near Monthly Limits


  • If you’re close to hitting your cap, manually pause until the next billing cycle


5. Switch to Monthly Budget (for Display & YouTube)


  • While not available for Search, this gives you precise control for video/display


Where to Check If You're Overspending


To see if your campaign is consistently going over budget:


  1. Go to Campaigns

  2. Click the “Budget” column

  3. Hover over the tooltip to see daily vs. actual spend

  4. Click into your campaign → Settings → Check delivery method & bidding strategy


Pro Tip: Add a budget pacing column in your reports to monitor overspend.


“But I Set My Budget — Why Does Google Still Spend More?”


Because your “daily budget” isn’t a strict cap — it’s more of a guideline. If your ad performs well or traffic spikes, Google’s system may spend more to try and hit your conversion goals.


This is especially true if you're using automated bidding strategies like:


  • Maximise Conversions

  • Target CPA

  • Target ROAS


They’re designed to use your full budget aggressively — and sometimes overshoot.


Final Takeaways: Don’t Panic, Just Plan


Google overspending your daily budget is normal — up to a point. But if you’re seeing excessive, frequent overspend with no return, it’s time to:


  • Revisit your bidding strategy

  • Audit your keywords and match types

  • Tighten your targeting

  • Set better campaign goals and limits


And if you're ever unsure — check the monthly spend total, not the daily spikes. Google should still stay within your monthly cap.

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