Someone pulls up a report showing social leads at a third the price of search leads, and the budget moves that afternoon. Six months later nobody can work out why revenue did not follow. Comparing cost per lead by channel is the most common way good budget decisions go wrong.
The short version: the cheapest enquiry is frequently the most expensive customer, and the only fair comparison happens after your close rate is applied.
This is for you if you split budget across more than one channel.
What cost per lead by channel looks like on paper
Start with the published figures, because they are where most people start.
Paid search averaged $66.69 across 13,474 US campaigns running April 2025 to March 2026. Facebook lead ads sit around $27.66 in LocaliQ’s most recent data, though that page discloses no sample size or date range, so hold it loosely.
Read like that, social wins by more than half. Which is exactly the conclusion that costs people money.
Why comparing cost per lead by channel this way misleads
Because the two channels are not selling you the same thing.
Search catches somebody who typed their problem into a box. Social interrupts somebody who was not thinking about you. One is further down the path, and it shows up in what happens after the enquiry arrives.
Ruler Analytics, working from 110 million sessions and £33.8 million of tracked spend across 13 industries, measured paid search converting at 5.4% against 2.11% for paid social, with an overall average of 5.13%.
Now run the arithmetic properly.
| Channel | Cost per lead | Close rate | Cost per customer |
|---|---|---|---|
| Paid social | $27.66 | 2.11% | ~$1,311 |
| Paid search | $66.69 | 5.40% | ~$1,235 |
The channel that looked less than half the price ends up slightly more expensive per customer. Not dramatically, which is the point. A comparison that looked decisive was actually close, and it pointed the wrong way.
The right way to compare cost per lead by channel
One rule: multiply by that channel’s own close rate before you compare anything.
Your close rates will not match the published averages, and that is fine. What matters is that you use a separate rate for each channel rather than one blended figure. Using a single close rate across channels reproduces exactly the error above, just with your own numbers.
That also means each channel needs its own ceiling. A search lead genuinely is worth more to you than a social lead, so it should be allowed to cost more. One target across everything hides whichever channel is quietly failing.
If you only change one thing after reading this, make it that.
Where organic fits
SEO behaves differently enough that putting it in the same table needs care.
There is no per-click cost, so once a page ranks the marginal enquiry is nearly free. That makes long-run organic cost per lead genuinely low, and it keeps falling as long as the page holds its position.
The honest caveats are two. Getting there takes months, so the early cost per lead is terrible and then improves, which no single figure captures. And reports showing organic beating paid in every industry tend to come from companies that sell SEO, which does not make them wrong but does earn a second look.
The practical answer is that organic and paid are not competitors. Paid buys you demand today and tells you which messages work. Organic compounds. Running both, with what you learn from one feeding the other, is entirely doable for one person and usually beats treating them as rival budgets.
The channel nobody measures
Referrals and word of mouth almost always have the lowest cost and the highest close rate, and they rarely appear in any report.
The reason is that nobody asks. Add one required question to your enquiry form, asking how the person found you, and compare the answers against what your analytics claims. The gap is usually large and it changes budget decisions.
I have had clients discover their best channel had no line in the budget at all, because it was never measured and therefore never credited. One of them had been quietly funded by an old partnership for two years. Nobody knew, so nobody had thought to do more of it.
Cost per lead by channel changes as you scale
A ranking that is true at one budget is not automatically true at another.
Each channel has a point where it runs out of cheap attention. Below that point extra money buys more of the same. Above it, costs climb, because you are reaching people further from buying.
That point differs by channel. A narrow, high-intent search campaign might exhaust its cheap volume at a few thousand a month. Meta, with far more inventory, can usually absorb more before the rise shows up.
So the practical rule is not “find the best channel and put everything there”. It is to fund the best channel up to the point where its costs start climbing, then move the next pound to the second-best. Splitting evenly because it feels balanced is how weak channels stay funded for years.
Watch for the moment a channel’s cost starts rising faster than its volume. That is the signal to stop adding, and most accounts miss it because nobody is looking for it.
What this year changed
The split moved underneath everyone.
Search lead costs fell for the first time in five years, driven by conversion rate rising for 87% of industries. Meanwhile Meta reported average price per ad up 12% year over year for the quarter ending 30 June 2026.
So a channel split decided eighteen months ago is running on prices that no longer hold. That is reason enough to redo the arithmetic this quarter, whatever conclusion you reach.
What to change this week
Four steps.
Work out a separate close rate for each channel, from the last 90 days, rather than one blended number.
Multiply each channel’s cost per lead by its own close rate, and rank on cost per customer instead of cost per enquiry.
Add a “how did you hear about us” question to your form so referral finally gets measured.
Then set a separate ceiling per channel and redo your split with this year’s prices.
The wider piece on judging lead cost covers the ceiling, the search figures and the Meta figures cover each side in detail, and why the two platforms moved in opposite directions explains the split. If organic is part of your plan, building traffic that survives a core update is where I would start. To have your channel mix looked at properly, get in touch.