How to Calculate Your Cost Per Lead and Break Even CPL

Cost per lead counts inquiries. Every call, form fill and chat the channel produced goes in the denominator, whether the caller wanted a roof replacement or a price on something you've never sold. Google Ads shows its own version of this as cost per conversion, which the help center describes as calculated by dividing your total cost by the number in your Conversions column. Your platform number and your real number drift apart quickly, because the platform counts what its tag can see and you count what actually rang.

Two things belong on the spend side that owners routinely leave out. The first is management, whether that's an agency retainer or the hours you spend in the account yourself. The second is the software the channel needs to work, usually call tracking and a landing page. If a campaign costs $5,000 in media and $1,000 in management, your spend is $6,000. Dropping that fee makes the channel look 20 percent cheaper than it is, since 1,000 divided by 5,000 is 0.20, and that's frequently the whole gap between a channel that pays and one that doesn't.

• Channel spend for one period, media plus fees plus software.
• Inquiries the channel produced in that same period.
• Qualified rate, the share of inquiries that were real prospects in your service area for work you sell. Write that definition down before you measure it, because what counts as qualified changes the answer more than any ad setting will.
• Close rate on qualified leads, jobs sold divided by qualified leads.
• Average job value, the price the customer pays.
• Gross margin, the share of that price left after materials, crew labor, subs, dump fees and permits. If you've never pinned this down, the job profit calculator gets you there from one recent job.

Those last two are where most of this falls apart. Owners know their revenue and guess at their margin, and a guess that's ten points high will tell you a losing channel is fine. Pull one recent job, total up what it actually cost you, and use that margin.

Say a Google Ads campaign spent $6,000 last month, management fee included, and produced 60 inquiries. Assume 60 percent of those inquiries were qualified, which is 36 of them, and that you closed 25 percent of the qualified ones, so 9 jobs. Your average job brings in $11,000, and your gross margin on that work runs 40 percent.

• Cost per lead: 6,000 divided by 60 equals $100.
• Qualified leads: 60 multiplied by 0.60 equals 36.
• Cost per qualified lead: 6,000 divided by 36 equals $166.67.
• Jobs booked: 36 multiplied by 0.25 equals 9.
• Cost per booked job: 6,000 divided by 9 equals $666.67.
• Gross profit per job: 11,000 multiplied by 0.40 equals $4,400.
• Gross profit from the channel: 9 multiplied by 4,400 equals $39,600.
• What's left after the spend: 39,600 minus 6,000 equals $33,600.

Three of those numbers describe the same $6,000 from different distances. An inquiry cost $100, a usable inquiry cost $166.67, and the customer who signed cost $666.67. Reports that only show the first number hide every quality problem a channel has, which is why it's worth comparing channels on the same outcome before you move budget between them.

The SBA defines a break even point as the point at which total cost and total revenue are equal, meaning there is no loss or gain for your small business. Apply that to a lead and you get the most that one inquiry can cost before the channel stops earning anything.

A lead is worth the gross profit it produces on average. In the example above, each lead turns into a job 15 percent of the time, because 0.60 multiplied by 0.25 equals 0.15. Each job carries $4,400 in gross profit. So each lead is worth 4,400 multiplied by 0.15, which is $660. That's your break even cost per lead.

Check it against the real numbers. At $660 a lead, 60 leads would cost 660 multiplied by 60, or $39,600, and those leads produced exactly $39,600 in gross profit. You'd have worked a month for nothing. At the actual $100 a lead you're spending 100 divided by 660, or 15.2 percent of your ceiling, and keeping the rest. Most owners set a target somewhere around a quarter of break even so a slow quarter still clears, which is the same reasoning behind Target CPA bidding in Google Ads, where Google notes that some conversions cost more than your target and some cost less while the average is what it steers toward.

Here's the trap. A shared lead marketplace quotes $30 a lead against your $100 paid search lead, and the $30 looks like an obvious win. Put both channels on the same $6,000 and run the same arithmetic. Assume the marketplace sends 200 inquiries, that 25 percent of them are qualified because the form is short and the intent is mixed, and that you close 8 percent of those because three other contractors bought the same name.

The $30 lead carries a cost per booked job of $1,500, because 6,000 divided by 4 equals 1,500. The $100 lead carries $666.67. Same budget, and the cheap channel returned $11,600 in gross profit while the expensive one returned $33,600. The bottom row is the cleanest way to see it: Channel B burns 34.1 percent of its own ceiling, since 30 divided by 88 equals 0.341, while Channel A burns 15.2 percent of a much higher one.

Plenty of contractors run marketplace leads at a profit. The headline price on its own just can't tell you whether yours will. Before you sign anything, work out what the channel's leads have to close at to beat what you're already running, then compare the two on booked jobs. If you want price ranges to sanity check a quote, our roofing lead cost benchmarks page keeps them in one place.

• Spend and jobs from different months. Roofing and restoration work closes on a lag, so September's spend often books in October. Hold spend and inquiries monthly, then recalculate close rate on a rolling 90 day window.
• Revenue standing in for gross profit. A $660 break even built on $11,000 of revenue would be $1,650, and you'd happily buy leads that lose money all year.
• Spam counted as leads. Every robocall in the denominator drags your cost per lead down and your close rate with it, which makes a bad channel read as a cheap one.
• Leads the channel didn't create. If you can't tell paid clicks from organic calls, the tags on your links are doing the sorting for you, and tagged links built in the campaign URL builder fix more attribution problems than any dashboard.
• One month treated as a trend. Nine jobs moves a lot when two of them slip. Give a channel a quarter before you judge it, and size the test from your close rate using a contribution based lead budget.

Pull last quarter's spend for one channel, count the inquiries it produced, mark which ones were qualified, count the jobs that came out the other end, and grab the gross profit on an average one. That's five minutes of looking things up and one page of division. Drop those figures into the lead cost calculator and it returns cost per lead, cost per qualified lead, cost per booked job and your break even ceiling together, which is the set you want in front of you before a renewal conversation. It sits with the rest of the free tools if you'd like to check the margin side on the same job first.