Cost per lead by channel: comparing social media and offline

Key takeaways

Cost per lead by channel is the total cost of a channel divided by the enquiries it produced in the same period. It is the fairest way to compare social media with traditional advertising, provided you count all the costs and only the enquiries worth having.

• Cost per lead = total channel cost ÷ enquiries from it.
• £500 of leaflets and 15 enquiries is £33 a lead.
• Count design, print and time, not just the media price.
• Count qualified enquiries, not every call.

What is cost per lead?

Cost per lead (CPL) is what you pay, on average, for one enquiry from a given source. A lead here means a person who asked about buying: a call, a form, a message or a visit. It turns very different channels into one comparable number.

• Social media marketing vs traditional advertising: what works better for SMEs?
• Cost per enquiry: what your website leads really cost

How do you calculate it?

Add up everything the channel cost in a period and divide by the enquiries you can trace to it in that period.

• 1. Choose a period, such as eight weeks.
• 2. Add media, production and time for the channel.
• 3. Count the enquiries traced to it.
• 4. Divide cost by enquiries.

• How to track offline advertising: six methods that work

What does a worked comparison look like?

Here is an illustrative comparison for a local service firm over eight weeks. The figures are invented to show the method, not market data.

• Leaflets: £500 ÷ 15 enquiries = £33.
• Paid social: £800 ÷ 32 enquiries = £25.
• Local magazine: £450 ÷ 6 enquiries = £75.
• Directory: £300 ÷ 10 enquiries = £30.

• Leaflets vs social media ads: which wins local customers?
• Directory listings vs social media: where buyers look now

Why is the lowest cost per lead not always the winner?

The lowest cost per lead can hide poor quality. If social media brings 32 enquiries and four become jobs, while the magazine brings six and three become jobs, the magazine's cost per customer is lower. Always take the sum one step further, to cost per sale.

• Paid social: £800 ÷ 4 jobs = £200 a customer.
• Local magazine: £450 ÷ 3 jobs = £150 a customer.

• How to measure social media lead quality
• How to compare advertising ROI across online and offline

What costs do people forget?

People forget their own time, design and production, and the cost of answering enquiries that go nowhere. At the April 2026 National Living Wage an hour costs about £16.27 with employer costs. Ten hours a month spent on a channel adds roughly £163 to its real cost.

• The hidden costs of traditional advertising
• Is social media marketing free? The real cost of 'free'

How do you trace enquiries to a channel?

Use a mixture of methods, because none is complete. Platforms report social media enquiries. Offline adverts need a code, a dedicated number or a short web address. Above all, ask every enquirer how they heard of you and write down the answer.

• 'How did you hear about us?' Asking the question properly
• Call tracking for small businesses: which advert made it ring?
• Set up UTM tracking for social media

How many leads do you need before deciding?

As a working rule, wait for at least 20 enquiries or six weeks, whichever comes later, before judging a channel. With five enquiries, one extra call changes the figure by a fifth. Paid social can be tested from £300–£500 a month, which is usually enough to reach a readable number.

• How to test an advertising channel in six weeks
• The minimum budget to test an advertising channel properly

Where does cost per lead mislead?

Cost per lead misleads when a buyer saw several channels before calling and only the last gets the credit. It also undervalues slow, brand-building activity. Use it to compare response channels, and judge awareness activity over a longer period.

• Marketing attribution for small businesses, kept simple
• Brand building vs sales activation: the small business view

What does this look like in practice?

A pattern we see with firms that start counting: the channel that produces the most enquiries is assumed to be the best, until the jobs won are counted. Quite often a quieter channel is supplying the customers who actually go ahead.

• See client work
• Social Media Marketing for UK businesses

Next step

Set up one simple sheet with a row per enquiry: date, source, and whether it became a sale. Eight weeks of rows will answer most budget questions.