Introduction
If you’re a UK ecommerce owner or lead generation marketer, you want to know how much Google Ads cost and how to budget your ad spend. In this guide, you’ll see average CPC (cost per click) by industry, understand agency fees, calculate customer acquisition cost (CAC), and learn how to split budgets between Search and Shopping campaigns. After reading, you’ll be confident planning your Google Ads budget and measuring returns.
What affects Google Ads cost in the UK?
Google Ads cost is mostly about the keywords you choose, your industry, competition, and your ad quality. You pay per click (CPC), not per impression.
Google runs keyword auctions every time someone searches. You bid for your ad to appear, but you only pay just enough to beat competitors. If many advertisers want the same keywords, prices go up.
Higher CPC usually means higher competition and more commercial intent. For example, "car insurance" costs more than "buy secondhand books." Location and device targeting can also change costs.
Your ad’s quality score, which Google calculates from relevance and experience, can reduce or increase your cost.
What is the average CPC in the UK by industry?
Average CPCs vary greatly:
- Retail and ecommerce: 30p to £1.20
- Legal and financial services: £2 to £5 or more
- Home services such as plumbers or electricians: £1 to £3
- B2B lead generation: £1.50 to £4
This means a click for a plumber could cost three or four times more than a click for a clothing retailer.
These averages come from platforms like WordStream and Google Keyword Planner [https://ads.google.com/home/tools/keyword-planner/]. Use tools to check your exact keywords.
What is the minimum viable budget for Google Ads?
You need enough budget to get meaningful results and data to optimise. For most UK small businesses, a minimum viable budget is about £500 per month.
With this, you can run multiple ads and test your message or bid approach. Spending less risks poor data and wasted spend on irrelevant clicks.
If you have less budget, focus on a very narrow set of high-intent keywords or use only Shopping campaigns.
Remember agency fees and time costs too.
Agency management fees vs ad spend
Many companies pay agencies to manage their Google Ads. Agencies charge a monthly management fee, often 10 to 20% of your ad spend.
For example, if your ad budget is £1,000 and the agency fee is 15%, you pay £150 plus the £1,000 in ads.
Some agencies have a minimum fee even if you spend less.
Managing campaigns yourself saves money but requires time and skill to avoid wasting your budget.
If you lack experience or time, an agency can help with optimisation and reporting, potentially improving returns despite the fee.
How to calculate customer acquisition cost (CAC)
CAC means the actual cost to get a customer from your ads. It’s essential to see if your campaigns are profitable.
To calculate CAC:
- Track your total Google Ads spend over a period.
- Count sales or leads directly coming from those campaigns.
- Divide ad spend by number of customers.
Example:
- £1,000 spent
- 50 sales generated from ads
- CAC = £1,000 ÷ 50 = £20 per customer
Compare CAC to your average customer lifetime value or profit margin to decide if ads make sense. Use the free profit margin calculator here: https://www.anthonymcgrath.co/tools/profit-margin-calculator/.
How to budget for search vs shopping campaigns?
Search campaigns show text ads when people type queries. Shopping campaigns show product images, prices and store name.
For ecommerce, Shopping usually drives better return on ad spend (ROAS) but needs a well-structured product feed and website.
Search campaigns work well for lead gen or brand awareness.
Budget split example
Try starting with 60% of your budget on Shopping campaigns and 40% on Search ads. Adjust monthly based on impressions, clicks and order value.
Monitor cost per acquisition by campaign type to optimise further.
Step-by-step process to plan your Google Ads budget
- Define your business goals: sales volume, leads, or revenue.
- Identify your average order value or lead worth.
- Research average CPC for your sector using Google Keyword Planner.
- Set a minimum monthly budget, ideally £500+.
- Calculate your target customer acquisition cost based on profit margins.
- Choose your campaigns: Search, Shopping or both.
- Allocate budget between campaigns.
- Set up conversion tracking (e.g., Google Analytics and Google Ads).
- Run campaigns and monitor performance weekly.
- Adjust bids, ads and budgets based on data.
- Consider agency support if you lack time or skills.
Common mistakes when budgeting Google Ads
- Setting budgets too low to collect meaningful data.
- Ignoring industry differences in CPC and competition.
- Overlooking agency fees leading to budget overruns.
- Not calculating CAC resulting in poor profit control.
- Putting all budget into one campaign type without testing.
- Forgetting to track conversions and attribute sales correctly.
Worked example: budgeting for a UK ecommerce store
Sarah runs an online jewellery shop. Her average order value is £80 with a profit margin of around 40% (about £32 profit).
She finds average CPC around 70p for her keywords.
Target CAC is £20 for profitability.
Sarah’s monthly budget plan:
- £500 ad spend
- 60% (£300) Shopping campaigns
- 40% (£200) Search ads
This budget should generate roughly 715 clicks (£500 ÷ £0.70). If 3% of clicks convert (21 sales), CAC is about £24, slightly above target, so Sarah plans to optimise bids and ads weekly.
Sarah also tracks website speed to avoid losing sales: https://www.anthonymcgrath.co/tools/site-speed-checker/
What it means for you
Knowing your Google Ads cost in the UK helps plan realistic budgets and targets. Average CPC and industry competition are vital costs to understand. Keep your CAC in check by calculating regularly. Manage your budget between Search and Shopping campaigns based on your services or products. Factor in agency fees if you hire help.
Check your website’s readiness before you spend for best results here: https://www.anthonymcgrath.co/blog/website-ready-for-ads
Start budgeting with confidence and control your ad spend smartly.
What to do next
If you’re ready to plan or optimise your Google Ads, first calculate profit margins and conversion costs using free tools like https://www.anthonymcgrath.co/tools/roas-calculator/ and https://www.anthonymcgrath.co/tools/profit-margin-calculator/.
Set up your account with a budget of at least £500 monthly and test Shopping and Search campaigns.
If you want professional help with setup or management, get in touch for advice: https://www.anthonymcgrath.co/#enquiry
Regularly monitor your campaigns and adjust bids to improve your customer acquisition cost and ROAS.
Good luck with your Google Ads budgeting.
