Customer acquisition cost — CAC — is one of the most important numbers in any marketing programme. It tells you how much you are spending to win each new customer, and when measured against customer lifetime value, it tells you whether your marketing is commercially sustainable.
Most businesses know they should be tracking CAC. Fewer calculate it correctly, fewer still benchmark it meaningfully, and many treat it as a metric to report rather than a lever to actively manage. This guide explains what CAC is, how to calculate it properly, what the numbers should look like, and the strategies that actually move it in the right direction.
What Customer Acquisition Cost Is
Customer acquisition cost is the total cost of acquiring a new customer, expressed as a cost per customer.
The formula is straightforward:
CAC = Total sales and marketing spend ÷ Number of new customers acquired
Both sides of that formula require some care to get right.
Total spend should include everything invested in acquiring customers — not just media spend. That means:
- Paid advertising spend across all channels
- Agency fees and contractor costs
- Salaries for sales and marketing staff (or the proportion attributable to acquisition)
- Software, tools, and technology used in acquisition campaigns
- Content production costs
- Events, trade shows, and promotional activity
Many businesses undercount CAC by including only their paid media costs and excluding the staff time and overhead that make those campaigns function. The result is a CAC that looks better than it is.
Number of new customers means genuinely new customers — not total customers, not repeat purchases, not reactivations. If your calculation includes returning customers in the denominator, your CAC will be artificially low.
CAC by Channel
Blended CAC — total spend divided by total new customers — is a useful headline number, but it hides as much as it reveals. The most commercially useful version of CAC is calculated by channel, because it tells you which acquisition routes are efficient and which are not.
Channel-level CAC varies enormously:
- Organic search (SEO) — typically has the lowest ongoing CAC of any digital channel once investment in content and technical SEO has compounded. The cost is front-loaded in content creation and takes time to build, but the marginal cost per customer decreases as the content asset base grows.
- Paid search (PPC) — moderate to high CAC depending on keyword competitiveness. Highly measurable, with direct attribution. CAC increases as bidding competition increases in a category.
- Paid social — highly variable. Can be low for products with strong visual appeal and broad consumer audiences; significantly higher for B2B or niche products where the audience is smaller and CPMs are elevated.
- Email marketing — once a list is established, email consistently delivers one of the lowest CACs of any channel, typically £1 to £5 per customer acquired for well-managed programmes.
- Referral and word of mouth — the lowest CAC of any channel where it can be engineered, because the acquisition cost is partially borne by the referring customer. A structured referral programme can deliver CAC 3 to 5 times lower than paid channels.
- Influencer marketing — CAC varies significantly by creator size and audience quality. Micro-influencers with highly engaged niche audiences often deliver better CAC than macro-influencers at higher fees.
Knowing your CAC by channel allows you to reallocate budget toward the most efficient routes and away from those that are not justifying their cost.
Read also-Brand loyalty explained
What Is a Good CAC?
There is no universal answer — CAC only means something in relation to two other figures: customer lifetime value (LTV) and your gross margin.
The CAC:LTV ratio is the most important benchmark. The widely used rule of thumb is that LTV should be at least 3 times CAC — a 3:1 ratio. Below this, the cost of acquiring customers is consuming too much of the value they generate. Above it, you may be under-investing in growth.
A few indicative industry benchmarks for context:
- E-commerce: CAC typically £15 to £80 depending on category, with fast fashion at the lower end and luxury at the higher end
- SaaS / subscription software: CAC of £100 to £500 is common, with higher LTV justifying higher acquisition spend
- Financial services: CAC typically £150 to £400 for retail products
- B2B services: CAC ranges from several hundred to several thousand pounds depending on deal size and sales cycle length
These are illustrative rather than precise, because CAC varies significantly within each category by brand maturity, competition, and acquisition channel mix. The most meaningful benchmark is your own historical CAC tracked over time — is it improving or deteriorating?
CAC and the Payback Period
Beyond the CAC:LTV ratio, the payback period is the other critical metric — how long it takes to recover the cost of acquiring a customer through the revenue or margin they generate.
A business with a CAC of £200 and a monthly margin contribution of £40 per customer has a payback period of five months. This is commercially healthy for most business models. A business with a CAC of £500 and a monthly contribution of £20 has a 25-month payback period — meaning it takes over two years to recover the cost of each new customer. This is only sustainable if customer retention is very high and churn is very low.
Payback period matters particularly for businesses with limited working capital, where a long payback period creates cash flow pressure even when the unit economics are theoretically sound in the long run.
For further data on CAC benchmarks by industry, check: HubSpot — customer acquisition cost by industry
Why CAC Rises Over Time — and What to Do About It
CAC has a natural tendency to increase over time in most digital channels. The mechanisms are well understood:
- Audience exhaustion — in paid channels, you reach the most responsive prospects first. As campaigns run, you move progressively toward less responsive segments of the audience.
- Increased competition — as a category grows, more advertisers bid on the same keywords and audiences, pushing CPMs and CPCs upward.
- Platform changes — algorithm shifts, iOS privacy changes, and cookie deprecation have all reduced the precision of digital targeting, increasing the cost per acquisition for many advertisers since 2021.
The strategies that counter CAC inflation are:
Invest in channels with decreasing marginal cost. Organic search, referral programmes, and email marketing all have cost structures that improve over time rather than deteriorate. A content library that compounds in SEO value is a structural CAC reducer.
Improve conversion rates. CAC is not just a function of how much you spend — it is a function of how many of the people you reach convert to customers. Improving landing page conversion rates, email sequences, and sales process efficiency reduces CAC without reducing spend.
Increase average order value or upsell rate. A higher average transaction value means each acquisition generates more revenue, which improves the LTV:CAC ratio without reducing CAC itself. This does not lower CAC but it makes the same CAC more commercially viable.
Build brand. Branded search is consistently cheaper than non-branded search. Customers who come to you because they already know and trust the brand have lower CAC than those who discover you through paid media for the first time. Long-term brand investment reduces CAC by increasing the proportion of demand that is inbound rather than acquired.
Retain customers and engineer referral. A customer who refers another customer effectively lowers your blended CAC. Systematic referral programmes, exceptional post-purchase experience, and loyalty mechanics all contribute to lower blended CAC by increasing the proportion of new customers who arrive at zero or near-zero acquisition cost.
Evershare builds acquisition strategies that are designed to deliver strong CAC performance from day one and improve over time — not just optimise the channels that are already deteriorating. Contact Evershare today.
For guidance on LTV:CAC ratio benchmarks, check: Paddle — SaaS benchmarks and metrics
Conclusion
Customer acquisition cost is the foundation metric of any marketing programme. Calculated correctly — including all costs, divided by genuinely new customers only — it tells you whether your marketing investment is commercially sustainable and which channels are working hardest for you.
CAC only tells the full story alongside LTV and payback period. A high CAC is not inherently a problem if LTV is proportionally high. A low CAC is not inherently a success if the customers acquired have short lifespans or low margin contributions.
The goal is not the lowest possible CAC — it is the best possible CAC:LTV ratio, improving over time through smarter channel allocation, better conversion, and the long-term brand and retention investments that bring more customers in at lower cost.
Frequently Asked Questions
What is a good customer acquisition cost?
There is no universal figure — CAC is only meaningful relative to customer lifetime value. The widely used benchmark is LTV at least 3 times CAC. What constitutes a good absolute CAC varies significantly by industry, business model, and margin structure.
Why is my CAC increasing over time?
Rising CAC is normal in digital channels and reflects audience exhaustion, increased competition, and platform changes reducing targeting precision. Countering it requires investing in lower-cost channels like SEO and referral, improving conversion rates, and building brand to increase the proportion of inbound demand.
Should CAC include staff salaries?
Yes — a properly calculated CAC includes all costs attributable to customer acquisition, including the proportion of sales and marketing staff salaries and overhead that supports acquisition activity. Excluding staff costs produces an artificially low CAC that understates the true cost of growth.
What is the difference between CAC and CPA?
Cost per acquisition (CPA) measures the cost of a specific action — a lead, a sign-up, a trial — while CAC measures the cost of acquiring a paying customer. CPA is a campaign-level metric; CAC is a business-level metric. A low CPA does not necessarily mean a low CAC if the conversion rate from the tracked action to paying customer is poor.