A £500 a month Google Ads budget for a small business buys roughly 165 clicks at the UK average of about £3 a click, and at a 5% conversion rate that is about eight enquiries.
That is the whole account in one line. Everything else in this article is about whether eight enquiries is worth £500 to you, and how to stop the number falling to three.
Most of the pages ranking for this question give a range (£500 to £1,500, £750 to £2,500) and leave it there. The range is not the problem. The problem is that nobody does the division, so business owners switch on a £16 a day campaign expecting it to behave like a £100 a day one.
The arithmetic at £3 a click
At £3 a click, £500 is 166 clicks before you have changed a single setting. The £3 figure is not invented. Whitehat's UK pricing roundup puts the average UK cost per click at £3.50 to £3.65, and Whito's indicative table has home services at £3.20 and healthcare and dental at £2.80. Whito is open that no primary UK-wide survey exists, so treat these as estimates, but £3 is a fair planning number for a trade or local service outside London.
Conversion rate is the second number. LocaliQ's 2025 benchmark report, built on 16,446 search campaigns, gives an average conversion rate of 7.52% across all industries. That is US data and a median across mature accounts, so for a new UK account with no history I plan at 5% and treat anything above it as a bonus.
166 clicks at 5% is 8.3 conversions. Call it eight. Cost per lead is about £60. If one in four of those enquiries becomes a job, £500 bought two customers at £250 each. For a boiler installer or a conveyancing solicitor that is fine. For a window cleaner at £15 a visit it is not.
Daily budget matters more at this level than people expect. £500 a month is £16.45 a day, and Google's own Target CPA help page tells advertisers to be comfortable spending up to two times the average daily budget on a busy day. Five clicks on a Monday morning can use the whole day. That is normal, and the account evens out across the month, but it means a single week of data tells you almost nothing.
Why Smart Bidding struggles with eight conversions a month
Smart Bidding needs conversion volume that a £500 account does not produce. Google's Target CPA page says that to judge the strategy you should measure the last 30 days, including at least 30 conversions. Its Smart Bidding setup guidance goes further: for consistent results it recommends at least 30 conversions per month per ad group, and its own table says campaigns under 30 conversions see cost per acquisition swing by up to 100% with a learning period of up to four weeks.
"We recommend you measure performance for the last 30 days, including at least 30 conversions." Google Ads Help, About Target CPA bidding
The same page says Target CPA can be started with no conversion history and "is effective for campaigns of all sizes". Both statements are true, and they describe different problems. You can switch Target CPA on at day one. What you cannot do with eight conversions a month is tell whether it is working, because the normal month-to-month swing is bigger than the signal.
There is a cost side too. LocaliQ's product lead, commenting on the 12.88% rise in average CPC in the 2025 report, said the sharper rises were on campaigns using Smart Bidding, because Google controls those bids directly. On a large account the algorithm pays more for clicks it judges likely to convert. On a £16 a day account it pays more and then runs out of money by lunchtime.
Google's own practitioner guidance hints at the answer. Its Smart Bidding best practices document lists Maximise conversions as "best for campaigns that are budget constrained" and Target CPA as best for campaigns that are not, and suggests portfolio bidding for campaigns with low conversion volumes. A £500 account is budget constrained by definition.
So the bidding sequence for a small account looks like this:
- Months one and two: Maximise clicks with a maximum CPC bid limit. Google says the cap "lets you steer the maximum amount you're willing to pay for each click", which stops one expensive term eating the day. Set the cap around your planning CPC. The job in these months is to prove conversion tracking fires and to build the search terms report.
- Month three onwards, if tracking is clean and the campaign is getting five or more conversions a month: Maximise conversions with no target. Google's budget-constrained recommendation.
- Target CPA only once the campaign has cleared 30 conversions in a 30 day window. For most £500 accounts that never happens, and that is fine.
Manual CPC is the other option for months one and two, and some advertisers prefer it because every bid is a decision they made. The difference at this scale is small.
£500, £1,000 and £2,000 side by side
The table below uses the same two assumptions throughout: £3 a click and a 5% conversion rate. Change either and the rows shift, but the relationships hold.
| Monthly budget | Daily budget | Clicks | Leads at 5% | Cost per lead | Google's 30 conversion threshold | Sensible bidding |
|---|---|---|---|---|---|---|
| £500 | £16.45 | 166 | 8 | £60 | Not reached | Maximise clicks with bid cap, then Maximise conversions |
| £1,000 | £32.90 | 333 | 17 | £60 | Not reached | Maximise conversions from month two |
| £2,000 | £65.80 | 666 | 33 | £60 | Reached, just | Maximise conversions, Target CPA from month three |
Two things stand out. Cost per lead does not improve as the budget grows, because the budget does not change the auction. A bigger budget buys more leads at the same price, not cheaper leads. And £2,000 is the first point where Google's own measurement threshold is met in a single campaign. That lines up with a UK Business Forums thread where a poster with a £2,000 a month budget was told it was "a reasonable amount for a small business" with enough room to pay someone to run it.
Now change the click price. This is where £500 either works or evaporates.
| Click price | Example sector (source) | Clicks from £500 | Leads at 5% | Cost per lead |
|---|---|---|---|---|
| £1.50 | Local trades, lower end (Whito) | 333 | 17 | £30 |
| £3.20 | Home services average (Whito) | 156 | 8 | £64 |
| £8.25 | Legal services average (Whito) | 60 | 3 | £165 |
| £15 | Personal injury solicitor, London (Whito) | 33 | 1 or 2 | £300 |
At £15 a click the account produces one or two enquiries a month, which makes it a lottery ticket with a monthly subscription.
Where a £500 Google Ads budget works for a small business
£500 works when the account is narrow enough that every click is a plausible customer. The pattern that holds up is one service, one town, exact and phrase match only, and a phone number in the ad.
One service, because the budget cannot test two. A plumber who sells boiler installs, bathroom fitting and emergency callouts should pick one. Boiler installs have the highest ticket, so that is where £16 a day belongs.
One town, because London clicks cost 15% to 30% more than the UK average and the rest of England sits 5% to 15% below it. A Kettering plumber targeting Kettering is paying the discount rate against local competitors. The same plumber targeting "Northamptonshire" is paying to show up in Northampton and Milton Keynes against firms twice the size.
Exact and phrase match, because Google's keyword help page says broad match is "the default match type that all your keywords are assigned" and shows ads on searches "related to" the keyword. Related is doing a lot of work in that sentence. On a large account broad match plus Smart Bidding finds searches you would not have thought of. On a £500 account it finds "plumbing apprenticeship" and "how to fix a dripping tap yourself", and there is no conversion volume for the algorithm to learn from its mistakes.
Call focused, because a phone call is usually the shortest path from click to job for a local service, which is why Google Ads for tradesmen usually makes the call the primary conversion. Count calls as conversions, set a minimum call length so a wrong number does not count, and put the number in the first screen of the landing page.
Tight hours, because a boiler installer who does not answer the phone at 11pm should not be paying for clicks at 11pm. Run the ads when someone picks up. Emergency plumbers are the exception, and they should be running a separate campaign anyway.
An older forum post from 2020 gives the flavour of what this looks like when it works: one UK Business Forums member reported that £50 of Google Ads brought in just over £600 of new business. That ratio is not typical and the post gives no detail, but it is the shape of a tight local account.
Where £500 a month is wasted
£500 is wasted where the click price or the margin makes the arithmetic impossible before the campaign starts. Three cases come up again and again.
Competitive London service terms. Whito's example is a solicitor paying about £6 a click in Manchester and £9 or more in London for the same work. At £9 the £500 account gets 55 clicks. At the LocaliQ legal conversion rate of 5.09% that is fewer than three enquiries a month, and the LocaliQ cost per lead for legal is $131.63 even on well-run US accounts. A London firm with £500 a month should spend it on its Google Business Profile and reviews instead.
Ecommerce brands with thin margins. Whito's worked example is a £20 product with £5 margin at £1.50 a click and a 5% conversion rate: £30 of clicks to make a £5 sale. The budget size is irrelevant. Nothing fixes that except a higher basket value, repeat purchase, or a different channel. Shopping campaigns have lower CPCs than search, but £16 a day across a product catalogue spreads too thin to tell which products are paying.
Anything that needs the algorithm. If your plan is Performance Max, broad match and Target ROAS, you are planning a campaign that Google's own guidance says needs 30 conversions a month to be measured. At eight a month you will be reading noise for a year.
A short decision list before you spend the first £500
Work through these in order. If any answer is no, fix that before the card goes in.
- Can you name one service and one town? If the honest answer is "all our services across the county", the budget is not big enough yet.
- Is the planning CPC under £5? Use the sector tables above or run the keyword through Keyword Planner. Above £5, £500 buys fewer than 100 clicks and the maths gets fragile.
- Is the average job worth at least ten times the expected cost per lead? At £60 a lead, that means a £600 job or a customer who comes back. Below that, the account can run at a loss while looking busy.
- Does conversion tracking fire on a call and a form, and have you tested it yourself? If not, you will have no idea whether eight leads happened.
- Can someone answer the phone during the hours the ads run? Missed calls at £3 each add up faster than you would think.
- Will you leave it alone for eight weeks? With £16 a day, a fortnight of data is 30 clicks. Changing bids on 30 clicks is guessing with extra steps.
- Have you written the negative keyword list before the campaign goes live, not after the first wasted month?
Our own rule at Growthcart is that we will run a £500 a month search account for a local service business, but we will not run one for a London legal term or a thin-margin product range, because the arithmetic has already decided the outcome. The budget is not too small to work. It is too small to work on the wrong job. A straight-talking UK Google Ads agency will tell you which before it takes the account.
If you want someone to check the numbers for your sector and town before you spend anything, our paid media team will do the arithmetic with you, or you can get in touch with the keyword and the postcode.