There is no single right budget for Google Ads, but there are clear parameters. Spend too little and you will not generate enough clicks to test anything; spend too much without tracking and you cannot tell if it is working. This guide gives specific budget guidance by firm size and location, and explains how to calculate what Google Ads should cost per new client.
The minimum viable budget
The minimum budget that generates enough data to make meaningful decisions in a UK market is approximately £200 to £300 per month.
Below this level, at typical local accounting keyword CPCs (£2 to £8 per click), you generate 30 to 60 clicks per month. If your landing page converts at five percent, that is one to three enquiries. Over four to eight weeks, you have enough information to see whether the campaign is producing results, but only just. Smaller budgets produce fewer data points and take longer to draw reliable conclusions.
A £100/month budget is not enough to test Google Ads for most UK accounting firms. It generates too few clicks per month to distinguish signal from noise.
Budget guidance by location and firm size
| Location type | Suggested starting monthly budget | Expected clicks | Expected enquiries |
|---|---|---|---|
| Small town or rural area | £150–250 | 30–60 | 1–4 |
| Mid-sized UK city | £300–500 | 60–150 | 3–10 |
| Major city (London, Manchester, Birmingham) | £500–1,000+ | 80–200+ | 4–15+ |
These figures are estimates based on typical local accounting keyword CPCs. Actual performance depends on keyword selection, ad quality, landing page conversion rate, and competition in your specific location. Higher competition in large cities increases CPC, which is why the London and major city budget recommendation is higher.
Calculating your target cost per new client
Work backwards from what a new client is worth to your firm:
- Average annual fee per new client: £1,500 (example — adjust for your actual average)
- Close rate from enquiry to signed client: 30% (i.e., three in ten enquiries become clients)
- Cost per enquiry target: £500 × 30% = £150 cost per enquiry would break even in year one (one client for £150 spend generates £1,500)
- Monthly budget to generate 10 enquiries at £150 per enquiry: £1,500
This is a simplified model. Accounting firms retain clients for multiple years, so the lifetime value of a client is typically three to five times the first-year fee. A cost per new client of £200 to £400 is sustainable for most practices when client lifetime value is factored in.
Run the same calculation for your own numbers before setting a budget.
The ramp-up approach
Rather than committing to a large budget immediately, a phased approach reduces risk:
- Month 1 to 2 (testing phase): £200 to £300/month. Goal: establish tracking, identify which keywords convert, build negative keyword list. Do not optimise for lowest cost yet — gather data.
- Month 3 to 4 (optimisation phase): £300 to £500/month. Goal: pause non-converting keywords, increase bids on converting ones, test landing page improvements. Cost per enquiry should start improving.
- Month 5+ (scaling phase): increase budget by 20 to 30% per month if ROI is positive. Once you have a cost per enquiry you are satisfied with, scale by increasing budget gradually. A sudden large budget increase can disrupt the campaign's optimised state.
What to do if the budget is not producing results
If you are spending £400/month and generating no conversions after six weeks:
- Check conversion tracking is working — submit your own form and confirm it registers.
- Review the search terms report — are you spending on irrelevant searches?
- Check where your ad traffic is going — homepage or a dedicated landing page?
- Check landing page conversion rate in GA4 — are visitors arriving and leaving immediately?
The most common causes of budget without results are: tracking not set up correctly (so conversions are happening but not recorded), broad keyword targeting attracting irrelevant traffic, and a poor landing page that does not convert.
What not to do with budget
Do not increase budget before tracking is in place. Spending more without knowing what the spend is producing accelerates the loss, not the gain.
Do not run a campaign for two weeks and give up. Google Ads typically takes four to eight weeks before its optimisation begins to show. Stopping after two weeks gives you no useful information.
Do not use Smart Campaigns or Google's automated "Express" setup. These give Google almost full control over keyword targeting and bidding and are optimised for Google's click revenue, not your conversion goals. Use standard Search campaigns with manual control.
Key takeaways
- The minimum viable monthly budget for meaningful data in most UK markets is £200 to £300.
- Budget requirements increase in competitive markets like London and major cities where CPCs are higher.
- Calculate your target cost per new client before setting a budget: client lifetime value, close rate from enquiry, and target enquiries per month determine whether a given budget makes commercial sense.
- Use a phased approach: testing phase (months 1–2), optimisation (months 3–4), scaling (month 5+).
- Never increase budget before conversion tracking is confirmed as working.
Frequently asked questions
Can Google Ads work on a £100/month budget?
Technically yes, but practically very difficult. At £100/month and a £4 average CPC, you get approximately 25 clicks per month. At a five percent conversion rate, that is one enquiry per month — not enough data to optimise or conclude whether the channel works. A £100/month budget is better invested in local SEO or content for most practices.
Should we spend more in January and July, when accounting demand is higher?
Yes. January (self-assessment) and the pre-April period (tax year-end) are peak search periods for accounting services. Increasing budgets by 30 to 50% in these periods and reducing slightly in quieter months like August and September is a sensible seasonal allocation.
How do we know when to stop running Google Ads?
If after three months of properly tracked, well-structured campaigns the cost per acquisition is higher than a new client's first-year fee, and there is no clear path to improvement, the channel may not be right for your market or positioning. Not every firm's target market uses Google Search to find an accountant — some rely entirely on referrals and LinkedIn.
What percentage of our marketing budget should go to Google Ads?
There is no universal answer. For a firm actively investing in client acquisition, Google Ads might represent 30 to 60% of a digital marketing budget. For a firm focused on organic growth and content, it might be 0%. Allocate based on demonstrated ROI, not category convention.
Should VAT be factored into the Google Ads budget?
Google Ads charges are subject to 20% UK VAT. If your firm is VAT-registered and recovers input VAT, the effective cost of a £300/month budget is £300 (with VAT recoverable). If you are not VAT-registered, the actual cost is £360 (£300 + £60 VAT). Factor this into your budget planning.