Cost per lead is the wrong number to optimise. Cost per acquisition is the number that determines whether your marketing is profitable. Here is how to calculate it and what to do with it.
Most trade businesses track cost per lead. Some track close rate. Almost none track cost per acquisition properly, which means they are making marketing budget decisions with incomplete information.
The business that knows its CPA by channel, by job type, and by week has a significant advantage over a competitor guessing based on cost per lead and gut feel. The number is not hard to calculate. Most businesses just have not set up the habit of tracking it.
CPA = total marketing spend divided by number of jobs won. Not cost per lead. Not cost per quote sent. Cost per signed, paid job.
That calculation includes lead costs, ad spend, any agency fees, and - if you are being rigorous - the staff time spent on sales that did not convert. For most trade businesses, the staff time component is not tracked at all, which means the real CPA is higher than the number most businesses report.
The key insight is that CPA tells you how profitable your marketing is. Cost per lead only tells you how expensive your leads are. A cheap lead with a low conversion rate produces a worse CPA than an expensive lead with a high conversion rate.
Formula: CPA = Total marketing spend / Jobs won
| Trade | Monthly spend | Jobs won | CPA | Avg job value | CPA as % of job |
|---|---|---|---|---|---|
| Roofing | $1,500 | 8 | $187.50 | $14,000 | 1.3% |
| Solar | $2,000 | 5 | $400 | $9,000 | 4.4% |
| HVAC | $800 | 6 | $133 | $5,000 | 2.7% |
The roofing example looks expensive on a per-lead basis but is highly efficient as a percentage of job value. The solar example is less efficient despite the strong absolute job value. These numbers change the conversation about whether to spend more or less on marketing.
As a rough benchmark: under 5% of job value is strong for most residential trade work. 5-8% is acceptable. Over 10% warrants a review of either spend or conversion process.
But this varies significantly by margin and job type. A roofing business with 35% gross margin can absorb a higher CPA as a percentage of job value than a solar business with 18% gross margin. The right CPA benchmark for your business is a function of your margin, not a universal number.
The more useful question is: what is your CPA trending over time? A CPA that is rising suggests either your spend is increasing without proportional conversion improvement, or your close rate is declining. Either is worth investigating immediately.
Three levers lower CPA without reducing spend:
None of these require spending less. They require converting better from the spend you already have. In most cases, improving process is faster and cheaper than finding a new channel.
Track CPA separately for each channel: Google ads, Meta ads, purchased leads, referrals. Most trade businesses average across all channels and miss the signal that one channel is producing $80 CPA and another is producing $600 CPA for the same job type.
The averaging problem is one of the most common and most expensive mistakes in trade marketing. A business spending $3,000 per month across three channels may be profitable on two and losing money on one. Without channel-level CPA tracking, that losing channel continues to consume budget that could be redirected to the profitable ones.
The fix is simple: tag every lead with its source at the point of entry. Track which source each won job came from. Calculate CPA for each source monthly. Then make budget decisions based on data rather than intuition.
Your average CPA hides your worst channel. Disaggregate it by source and the decision about where to invest next becomes obvious.
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