There is a number buried in your Google Ads account that nobody talks about. It is the amount of money you spend every month paying for clicks from people who were going to visit your website anyway. For most businesses, that number is surprisingly large.

Brand campaigns — the ones targeting your own company name — consistently show the highest ROAS in any account. They look like your best investment. But as we explain in why brand ROAS is a lie, the maths tells a different story when you account for organic cannibalisation.

This article walks through exactly how to calculate your wasted brand spend, with worked examples at different budget levels.

The Cannibalisation Problem

When someone searches for your brand name on Google, they typically see two things: your paid ad at the top, and your organic listing just below it. If your ad is running, a significant portion of people will click the ad. If it is not running, those same people will click the organic listing instead.

This is cannibalisation. Your paid ads are eating into traffic that your organic listing would have captured for free. Every cannibalised click is money spent for no incremental benefit.

Research consistently shows that 60-90% of brand ad clicks would have occurred organically if the ads were not present. Google's own studies (which have every incentive to show ads in a favourable light) found that 89% of ad clicks are incremental for non-brand terms, but only around 50% for brand terms. Independent studies typically find even lower incrementality rates for brand searches.

The exact cannibalisation rate for your business depends on factors like your organic ranking position, the competitiveness of your market, and whether competitors are bidding on your brand terms. But for most businesses with a strong organic presence, cannibalisation rates of 70-80% are common.

The Formula

Calculating your wasted brand spend is straightforward once you know the inputs.

Wasted Brand Spend = Total Brand Spend x Cannibalisation Rate

The cannibalisation rate is the percentage of paid brand clicks that would have occurred organically. If you have not run an incrementality test, a conservative estimate is 70%. For well-established brands with strong organic rankings and no competitor brand bidding, 80% is more realistic.

Your true incremental cost per acquisition on brand campaigns is:

Incremental CPA = Total Brand Spend / (Total Brand Conversions x (1 - Cannibalisation Rate))

This is the number that should keep you up at night.

Worked Example: Small Business (£2,000/month Brand Spend)

Let us say you run a regional services business spending £2,000 per month on brand campaigns.

| Metric | Value | |---|---| | Monthly brand spend | £2,000 | | Brand clicks | 4,000 | | Brand conversions | 200 | | Reported CPA | £10 | | Reported ROAS | 15x |

Your agency tells you this is your best-performing campaign. And on paper, it is. A £10 CPA and 15x ROAS looks exceptional.

Now apply a 75% cannibalisation rate:

| Metric | Value | |---|---| | Cannibalised clicks (75%) | 3,000 | | Truly incremental clicks | 1,000 | | Cannibalised conversions | 150 | | Truly incremental conversions | 50 | | True incremental CPA | £40 | | True incremental ROAS | 3.75x | | Wasted spend | £1,500/month |

That £10 CPA is actually £40 when you account for cannibalisation. The 15x ROAS drops to 3.75x. And you are wasting £1,500 every month — £18,000 per year — paying for clicks you would have received for free.

Worked Example: Mid-Market Business (£10,000/month Brand Spend)

Now consider a mid-market ecommerce business with higher brand spend.

| Metric | Value | |---|---| | Monthly brand spend | £10,000 | | Brand clicks | 25,000 | | Brand conversions | 1,000 | | Reported CPA | £10 | | Reported ROAS | 12x | | Average order value | £120 |

Apply a 70% cannibalisation rate:

| Metric | Value | |---|---| | Cannibalised clicks (70%) | 17,500 | | Truly incremental clicks | 7,500 | | Cannibalised conversions | 700 | | Truly incremental conversions | 300 | | True incremental CPA | £33.33 | | True incremental ROAS | 3.6x | | Wasted spend | £7,000/month |

That is £84,000 per year in wasted brand spend. For many mid-market businesses, that budget could fund an entire non-brand campaign strategy that generates genuinely new customers.

Worked Example: Enterprise (£50,000/month Brand Spend)

For larger advertisers, the waste compounds dramatically.

| Metric | Value | |---|---| | Monthly brand spend | £50,000 | | Brand clicks | 100,000 | | Brand conversions | 4,000 | | Reported CPA | £12.50 | | Reported ROAS | 10x | | Average order value | £125 |

With an 80% cannibalisation rate (typical for well-known brands):

| Metric | Value | |---|---| | Cannibalised clicks (80%) | 80,000 | | Truly incremental clicks | 20,000 | | Cannibalised conversions | 3,200 | | Truly incremental conversions | 800 | | True incremental CPA | £62.50 | | True incremental ROAS | 2x | | Wasted spend | £40,000/month |

£480,000 per year. That is not a rounding error. That is a substantial budget that could be driving real growth through non-brand acquisition.

How to Calculate Your Own Numbers

You can run these calculations yourself in a few minutes. You need three things from your Google Ads account:

Monthly brand campaign spend — pull this from the campaign report
Monthly brand conversions and revenue — same report
An estimated cannibalisation rate — use 70% as a starting point, or better yet, run an incrementality test

Want to skip the spreadsheet? Our brand bidding calculator does the maths for you. Enter your brand campaign data and it will show you your estimated waste, true incremental CPA, and potential savings.

The Redirect Argument

Here is where the numbers get interesting. The question is not just "how much am I wasting?" but "what could that budget do elsewhere?"

Non-brand campaigns typically have lower reported ROAS than brand campaigns. A non-brand campaign might show a 3x ROAS compared to a brand campaign's 12x. This is why most advertisers resist shifting budget away from brand. Understanding the real difference between branded and non-branded keyword budgets is essential before making any reallocation decisions.

But the incremental picture is reversed. Non-brand campaigns have much higher incrementality — typically 70-90% of clicks are genuinely incremental, compared to 20-30% for brand. When you compare incremental ROAS, non-brand campaigns often outperform brand campaigns.

Using the mid-market example above: if you redirected £7,000 of wasted brand spend to a non-brand campaign with a 4x reported ROAS and 80% incrementality, you would generate:

Non-brand revenue: £28,000
Incremental non-brand revenue (80%): £22,400
Compare to incremental brand revenue from the same £7,000: £4,200

The redirected budget generates over five times more incremental revenue. The numbers are not even close.

Why Your Agency Might Not Tell You This

Brand campaigns make agencies look good. They inflate account-level ROAS, reduce blended CPA, and create the impression that the account is performing well. Removing brand campaigns from the equation often makes the rest of the account look worse on paper.

This does not mean your agency is acting in bad faith. Many account managers genuinely believe brand campaigns are essential. They have been trained on reported ROAS as the primary metric, and by that measure, brand campaigns are indeed top performers.

But the incentives are misaligned. The agency bills a percentage of spend or charges management fees. More spend means more revenue for them. Recommending that you cut brand spend by 70% is recommending that the agency earns less.

The best agencies proactively analyse incrementality and recommend budget shifts that maximise true ROI. If your agency has never raised the topic of brand cannibalisation, that tells you something.

What You Should Do Next

Step 1: Run the numbers. Use the formula above or our brand bidding calculator to estimate your wasted spend. Even a rough estimate will give you an idea of the scale of the problem.

Step 2: Check for competitor activity. Before making any changes, determine whether competitors are bidding on your brand terms. If they are, you may need to maintain some level of brand coverage. Run a free brand bidding audit to see who is currently targeting your keywords.

Step 3: Run an incrementality test. Estimates are useful, but real data is better. A geo-based incrementality test takes 2-4 weeks and gives you precise cannibalisation rates for your specific business.

Step 4: Reallocate gradually. Do not switch off brand campaigns overnight. Reduce bids by 20-30% each week, monitor organic traffic recovery, and redirect the freed-up budget to non-brand campaigns with proven incremental value.

Step 5: Monitor continuously. The competitive landscape changes. Set up ongoing monitoring so you know immediately if a competitor starts bidding on your brand terms, and can respond accordingly.

The Cost of Inaction

Every month you do not address brand cannibalisation, you are writing a cheque to Google for traffic that would have arrived at your site for free. For a business spending £10,000 per month on brand campaigns, that is potentially £84,000 per year in waste.

The maths is not complicated. The data is available. The only question is whether you are willing to challenge the comfortable narrative that your brand campaign is your best performer.

It is not. It is your most expensive way of acquiring traffic you already own.

How Much of Your Brand Ad Spend Is Wasted? Calculate Your Hidden Cost