How much should a tradesman spend on Google Ads? Work it out from your own numbers

Why is there no single answer?

Because a budget that’s fine for one trade would sink another. A full re-roof and a gutter clear are both roofing work, but what you keep from each is miles apart, and so is what you can afford to pay to win it.

So I won’t give you a figure. We don’t publish them, and a number off the internet tells you nothing about your jobs or your towns. What I can give you is the method. It’s four sums and two of Google’s own tools, and every number in it is yours.

Step 1: what do you keep from an average job?

Start with what’s left over, not the invoice. Take your last 10 jobs of the kind you want more of. For each one, take the price and knock off materials, labour, skip hire, fuel and anything else the job ate. Average what’s left.

Call that K: what you keep from an average job.

If your work varies a lot, do this separately for each type of job. Repairs and full installs are two different budgets.

Step 2: how many quotes do you win out of 10?

Look at your last 10 or 20 quotes and count how many turned into work. If you won 3 out of 10, your win rate is 3 ÷ 10, or 0.3.

Call that W.

Be honest about the enquiries that never got as far as a quote: wrong area, wrong job, or people who went quiet. You pay for those too. Across the Facebook enquiries we’ve read for clients, in the six reviews that counted it exactly, 72 of 236 real enquiries never replied to anything. Google enquiries behave differently, but the lesson carries over. If plenty of yours never reach a quote, count jobs won out of every 10 enquiries instead.

Step 3: what is one enquiry worth to you?

Multiply the two:

V = K × W

V is what an average enquiry is worth to you before you’ve spent anything on ads.

Here’s an example with made-up round numbers, just to show the sum. Say you keep £800 from a job and win 3 in 10. Then V = £800 × 0.3, which is £240. That’s not a typical figure for any trade. Put your own numbers in.

Step 4: what’s the most you can pay for an enquiry?

If you hand all of V to Google, you’re working for nothing. Decide what share of it you’re happy to spend to win work. Call that share S.

M = V × S

M is the most you can pay for an enquiry and still make money. In the example, if you were happy to spend half, M would be £240 × 0.5, so £120 for an enquiry.

Two more numbers turn that into a budget:

• R, the share of clicks that become an enquiry. If 1 in 10 people who click go on to ring, message or fill in the form, R is 0.1. The most you can pay for a click is M × R, a tenth of M in that case. You won’t know R for sure until ads have run, and it depends a lot on the page people land on.
• E, the number of enquiries you can actually handle in a month. Be realistic about the diary.

Your monthly budget is then E × M. Anything above that buys enquiries you can’t get to or can’t afford.

How do you find what clicks cost in your area?

Google shows you, in its Keyword Planner. You need a Google Ads account first: Google’s help page says you must complete your account setup by entering your billing information to use it. Then:

1. Open Keyword Planner from the tools menu in Google Ads and choose Discover new keywords.
2. Type in the jobs people search for, like “roof repair” or “new driveway”.
3. Change the location to the towns you cover, not the whole UK.
4. Look at the two bid columns.

Google explains them on its Keyword Planner forecasts page. “Top-of-page bid (low range)” is “an approximation of the 20th percentile” of what advertisers have historically paid, and the high range is “an approximation of the 80th percentile”, both “based on your location and Search Network settings”.

Compare those with your click ceiling, M × R. If the high range for your main searches sits well above it, Google may not pay for itself on those searches unless your win rate or your page improves. Google also warns that “you can expect results to be less accurate if you’re targeting a small geographic location”, so treat the figures as a guide for a single town.

Why does a too-small budget hold you back?

Because Google’s automated bidding learns from conversions: the calls, messages and forms you tell it to count. Google says on its Target CPA page that “advertisers can start using Target CPA with no conversion history”. It also says: “For evaluation, we recommend that you measure performance for the last 30 days, including at least 30 conversions.”

Its Smart Bidding page says the same thing: Google “recommends measuring performance over longer time periods that have at least 30 conversions, such as a month or longer”.

If your budget only buys a handful of enquiries a month, it takes a long time to reach that, and until you do, neither you nor Google can tell what’s working. If money is tight, narrow it down. Fewer towns and only the jobs worth most to you will teach Google more than a thin spread across everything.

Does the time of year change what you should spend?

For a lot of trades, yes. You can see the pattern for yourself in Google Trends:

1. Type in your trade, like “tree surgeon” or “roofer”.
2. Set the location to the United Kingdom, or narrow it down if your part of the UK has enough searches.
3. Set the time range to the past 5 years and look for the months that rise every year, not just once.

The numbers aren’t search counts. Google’s Trends FAQ says they’re “scaled on a range of 0 to 100 based on a topic’s proportion to all searches on all topics”, and that “search terms with low volume appear as ‘0’”. So use broad terms, not a narrow job in one small town.

For Facebook enquiries we measured the month-by-month pattern across our own clients in the busiest months for trade enquiries. Whatever the source, only raise your budget for a busy month if you can take the work on.

Why judge Google Ads by cost per booked job, not cost per click?

Cheap clicks that never ring are the most expensive clicks you’ll buy. What matters is what each job cost you to win:

Cost per booked job = what you spent ÷ jobs booked from it

Compare that with K. If a booked job costs you less than you keep from it, the ads are paying their way, whatever the clicks cost. The cost per job calculator works it out from your own spend, enquiries, reply rate, win rate and job value.

To do this you have to count enquiries and mark which ones became work. It’s why our Google Ads for tradesmen reports show booked jobs and cost per job, not just clicks.