To calculate cost per lead, divide your total marketing spend by the number of leads you got. If you spent £500 and received 25 enquiries, your cost per lead is £20. That is the whole formula: CPL = total spend ÷ number of leads.
A lead is simply someone who has asked to hear from you, for example by filling in a form, calling, or sending a message. The number is useful, but it only tells half the story. What really matters to your business is how much it costs to win a new customer, and that can be very different.
In this guide I will show you the formula, a few worked examples, how to include management fees for a true figure, how to work out what a good cost per lead looks like for your business, and ways to bring it down.
The cost per lead formula
Cost per lead (often shortened to CPL) is the average amount you pay to generate one enquiry. The formula is:
Cost per lead = total spend ÷ number of leads
Pick a time period, such as one month or one campaign, and use the same period for both numbers. Mixing a month of spend with a week of enquiries will give you a misleading answer.
What counts as a lead?
Decide this before you start counting, and stick to it. For most small businesses a lead is one of these:
- A contact form submission
- A phone call from an advert or your website
- A booking request or quote request
- A message through Facebook, Instagram or WhatsApp that asks about your service
Do not count clicks, likes or page views as leads. Someone who clicked your advert has not yet told you they want to buy. If you are not sure how many enquiries your marketing is really producing, proper tracking is the first thing to put right.
What counts as spend?
The simplest version uses only your advertising spend, the money paid to platforms such as Google or Meta (the company behind Facebook and Instagram). That is a fine starting point and it is how most platforms report it.
The more honest version is your true cost per lead, which also includes anything else you paid to get those leads:
- Management fees for whoever runs your campaigns
- Design or video costs for the adverts
- Any software or call tracking you pay for specifically to run the campaign
If you are weighing up what you spend overall, my guide on how much a small business should spend on marketing may help.
Worked examples
These first two are hypothetical examples to show the maths. The numbers are made up, but the method is exactly what you would use.
Example 1: ad spend only
Imagine a plumber in Kent spends £600 on Google Ads in a month and receives 30 enquiries (phone calls and form submissions combined).
£600 ÷ 30 = £20 per lead.
Example 2: true cost per lead with management fees
Now imagine the same plumber pays a management fee of £450 a month to someone to run the campaign. Ad spend is paid to the platform separately, so the total cost of getting those leads is £600 + £450 = £1,050.
£1,050 ÷ 30 = £35 per lead.
Same campaign, same enquiries, but a very different figure. Neither number is wrong. The first tells you how efficient the adverts are. The second tells you what the leads really cost your business. When you are deciding whether marketing is worth it, the true figure is the one to use. It is also a fair way to judge whether professional Google Ads management pays for itself: a good manager should bring the cost per lead down by more than the fee adds.
Example 3: comparing two campaigns
Say you run two campaigns in the same month:
- Campaign A: £300 spend, 10 leads, so £30 per lead
- Campaign B: £200 spend, 10 leads, so £20 per lead
On cost per lead alone, Campaign B looks better. But that is only the first question, which brings us to the bigger point.
Cost per lead vs cost per acquisition
Cost per acquisition (CPA) means the cost of winning a new customer. The formula is just as simple:
Cost per new customer = total spend ÷ number of new customers
The two figures answer different questions. Cost per lead asks, “How much does it cost to get someone to get in touch?” Cost per new customer asks, “How much does it cost to get someone to actually buy?” A cheap lead that never becomes a customer is not cheap at all.
Go back to Campaign A and B. If Campaign A’s 10 leads turned into 5 customers, its cost per new customer is £300 ÷ 5 = £60. If Campaign B’s 10 leads turned into 2 customers, it is £200 ÷ 2 = £100. The “more expensive” campaign is actually the better one.
A real example: Halo Gym
Here is a real campaign. For Halo Gym in Tunbridge Wells, I ran a Meta Ads 50% off campaign. The numbers:
- Ad spend: £474.59
- Membership enquiries: 100
- New paying members: 49
- Lead-to-member conversion: 49%
The cost per lead was £474.59 ÷ 100, which is about £4.75 per enquiry. The cost per new member was £474.59 ÷ 49, which is £9.69 per new paying member. The campaign delivered a 215% advertising ROI (return on investment, meaning how much money came back compared with what was spent).
Notice that £9.69 is not a cost per lead. It is the cost of each person who joined and started paying. Both figures matter, and they sit together: the cost per lead shows how well the advert attracts interest, while the lead-to-member rate shows how well the gym turns that interest into members. You can read the full story in the Halo Gym Meta Ads case study. Results vary from business to business, so treat these as an illustration of the method rather than a promise.
What is a good cost per lead?
There is no single good number. A £50 lead can be a bargain for a business selling a £5,000 service, and a £5 lead can be a loss for a business selling a £20 product. What is good depends on what a customer is worth to you and how many leads turn into customers.
Here is a formula for the most you can afford to pay:
Maximum affordable CPL = customer value × lead-to-customer rate
Use profit, not just sales, for customer value if you can. Then use the percentage of leads that become customers, written as a decimal (20% is 0.2).
Worked example
Imagine a beauty clinic where a typical new client is worth £300 in profit over the time they stay, and 1 in 5 enquiries (20%) becomes a client.
£300 × 0.2 = £60.
At £60 per lead the clinic would break even. So a good target is well below that, say £25 to £30, so there is profit left over. If their leads currently cost £15, they have plenty of room to spend more and grow. If they cost £80, something needs fixing.
Notice what moves the answer: if you improve your follow-up and 1 in 3 enquiries becomes a client, your maximum affordable CPL rises to £100 without changing your marketing at all. Your sales process is part of your marketing maths.
If you want to link your spend directly to revenue, my guide to how to calculate ROAS (return on ad spend, the sales you get back for every £1 spent on ads) is the natural next step.
How to reduce your cost per lead
Once you know your number, here are the practical levers that tend to bring it down.
1. Make your website convert better
If your advert gets the click but the page does not persuade, you are paying for visitors who leave. A clear headline, a visible phone number, a short form and proof that you are trustworthy all help. Start by working out your website conversion rate, which is the percentage of visitors who get in touch. Even a small improvement lowers your cost per lead without any extra ad spend.
2. Tighten your targeting
On Google Ads, that means showing your adverts only to people searching for what you actually sell and adding “negative keywords” (words you tell Google to avoid, such as “free” or “jobs”). On Facebook and Instagram, it means choosing a clear local audience and a strong offer rather than showing ads to everyone. A tailored approach to Facebook and Instagram advertising can make a big difference here.
3. Improve your adverts and your offer
An advert that speaks directly to a customer’s problem, with a clear next step, usually earns more enquiries from the same budget. A strong, time-limited offer can also work well, as the Halo Gym campaign showed.
4. Make it easy to enquire
Every extra form field costs you leads. Ask only for what you need. Add a click-to-call button for mobile visitors. Make sure forms work properly, because a broken form quietly wastes your whole budget.
5. Cut what is not working
Look at your spend by campaign, keyword or advert. If some are eating budget and producing no enquiries, pause them and move the money to the ones that perform.
6. Respond quickly
This will not change your cost per lead, but it improves your cost per new customer, which is the figure that counts. Replying to enquiries within minutes rather than days often turns more of them into paying customers.
7. Compare your channels
Your cheapest leads may not come from where you expect. Comparing cost per lead and cost per customer across Google, Meta, your Google Business Profile and your website helps you put money where it works. My article on which marketing channels bring customers explains how to think about this.
Common mistakes to avoid
- Counting the wrong things as leads. Clicks and likes are not enquiries.
- Ignoring fees. Leave out management costs and your figure looks better than reality.
- Judging by cost per lead alone. Always check how many leads become customers.
- Using too short a time period. A week of data can swing wildly. A month or more gives a steadier picture.
- Not tracking where leads come from. If you cannot tell which source produced an enquiry, you cannot calculate anything reliably.
Frequently asked questions
What is the formula for cost per lead?
Cost per lead equals total spend divided by the number of leads. For example, £400 spent to generate 20 enquiries gives a cost per lead of £20. For a fuller picture, include management fees and any other costs of running the campaign in your total spend.
What is the difference between cost per lead and cost per acquisition?
Cost per lead is what you pay to get an enquiry. Cost per acquisition, or cost per new customer, is what you pay to win a paying customer, calculated as total spend divided by new customers. Halo Gym’s campaign cost about £4.75 per enquiry but £9.69 per new paying member.
What is a good cost per lead for a small business?
It depends on how much a customer is worth to you. Multiply your customer value by the percentage of leads that become customers to find the most you can afford to pay per lead. Then aim for a figure comfortably below that, so you make a profit.
Should I include management fees in my cost per lead?
Yes, if you want your true cost per lead. Ad spend alone shows how efficient the adverts are, but adding management fees shows what your leads really cost the business. It is worth tracking both numbers.
How can I lower my cost per lead quickly?
The fastest wins are usually fixing your tracking, pausing campaigns or keywords that produce no enquiries, simplifying your enquiry form and making your landing page clearer. Results vary, and the bigger gains tend to come from steady testing over a few months.
Want help working out your numbers?
If you are not sure what your leads are really costing you, I can help. Request a free digital audit and I will look at where your enquiries are coming from, what they cost and where there is room to improve. Prices for ongoing support are on the pricing page.
Or if you would rather talk it through, get in touch. You will work directly with me, and if we grow you, we grow together.
Want help putting this into practice?
