Customer acquisition cost (CAC) is the total investment a brand makes to win a single new customer. In 2026, that number is under more pressure than ever. OneSignal’s State of Customer Messaging report found that most respondents allocated more resources toward customer acquisition than retention. IAB’s 2026 Outlook Study confirmed that rising acquisition costs are now one of the defining pressures reshaping how brands plan and allocate media spend.
According to HubSpot’s 2025 Cost per Lead (CPL) and Customer Acquisition Cost (CAC) Benchmarks report, acquisition costs vary significantly by channel, making channel-level benchmarking useful for deciding where to invest. To help brands understand how to accurately measure their customer acquisition cost and strategically implement a plan based on those insights, we laid out everything advertisers need to know about customer acquisition costs, specifically within affiliate marketing.
Key Takeaways
- CAC is the all-in cost your brand incurs to acquire a single new customer, and measuring it accurately requires alignment on exactly which inputs you are including across every channel and partner.
- Affiliate marketing can be highly CAC-efficient when partner economics, tracking, and incrementality are managed well, because spend is more closely tied to defined outcomes than impression- or click-based media.
- As overall acquisition costs continue to rise, brands that benchmark CAC by channel can make more informed decisions about where performance-based channels fit in the mix..
- Understanding your CAC is not just a finance exercise. It is the foundation for making smarter decisions about where to grow your affiliate program.
What is customer acquisition cost?
Customer acquisition cost (CAC) is a comprehensive performance metric representing the total sales and marketing spend required to convince a potential lead to purchase a product or service. In partnership marketing, CAC serves as a primary efficiency benchmark for evaluating channel scalability.
Getting this number right matters more than ever in 2026. As the IAB’s 2026 Outlook Study notes, customer acquisition remains the top objective for buyers even as brands rebalance their growth strategies as acquisition costs rise. Brands that do not have a clear handle on their CAC by channel are flying blind in an environment where every dollar has to work harder.
What metrics do you need to understand your customer acquisition cost?
The most important metric to understand alongside CAC is cost per action (CPA). While CPA measures the cost of a single conversion, CAC is the all-in number: it accounts for all marketing spend plus any additional costs your business incurs to acquire a net new customer. Those additional costs could include agency spend, employee salaries, gifting costs, technology stack, network costs, and more. CAC should not include sales tax.
Before diving into best practices around using CAC, consider how you are using the term internally. It is critical that you have alignment within all your marketing channels and partners on exactly which metrics you are including in your CAC calculations, as the exact inputs can vary from business to business.
Why is affiliate marketing one of the most cost-efficient acquisition channels?
Affiliate marketing earns that reputation because of one structural advantage: you only pay when a conversion happens. That performance-based model means your CAC is directly tied to actual results rather than ad spend that may or may not convert. Impact’s State of Affiliate Marketing 2025 report found that 74% of brands generate 11% to 30% of total revenue from affiliate marketing, underscoring the channel’s material role in the broader performance mix.
eMarketer’s 2026 affiliate marketing forecast puts the scale in context: US advertisers will spend $13.81 billion on affiliate marketing this year, up 11.3% from 2025, reflecting a channel that has become a core component of ecommerce infrastructure. The scalability of affiliate programs means you can control acquisition volume by adjusting partner incentives, supporting CAC forecasting as you grow. Based on Impact’s 2025 Industry Trend Benchmark Report, which tracked nearly one billion transactions across North American brands, average order value increased 4% year over year even as transaction volume declined.
How to calculate your CAC within affiliate marketing
The basic formula is straightforward:
CAC = Total affiliate marketing costs / Total number of new customers acquired
Your total affiliate marketing costs should include commissions paid to partners, network or platform fees, agency or management fees, technology costs, and any creative or content costs associated with the program. What it should not include is sales tax.
The most important thing is consistency. Whatever you decide to include, make sure every team and partner is working from the same definition. CAC can vary significantly from business to business depending on what is counted, and internal misalignment makes benchmarking and optimization nearly impossible.
How do you manage and reduce CAC in your affiliate program?
Knowing your CAC is only useful if you act on it. Here is how brands are putting the number to work in 2026:
Calculate CAC by partner, not just by channel. Blended CAC across your affiliate program can hide significant variation between partners. Some affiliates will deliver customers at a fraction of your average CAC. Others will cost more than paid search. Knowing which is which lets you invest accordingly.
Benchmark against your customer lifetime value (LTV). A CAC of $150 means very different things depending on whether your average customer spends $200 or $2,000 over their lifetime. The goal is not to minimize CAC in isolation but to maintain a healthy LTV to CAC ratio, typically 3:1 or better.
Use CAC to evaluate new partner opportunities. Before bringing on a new affiliate partner, use your existing CAC benchmarks to set expectations and structure compensation. Performance-based commission structures keep CAC more accountable as you scale the program.
Revisit your CAC calculation as the program grows. As you add new partners, tactics, and markets, the inputs that make up your CAC will shift. Building a regular cadence for reviewing and recalibrating your calculation keeps your data accurate and your decisions grounded.
Acceleration Partners helps brands build and manage affiliate programs with a clear focus on measurable outcomes, including CAC. If you are looking to get more from your affiliate investment, let us show you how.
Frequently asked questions
What is a good CAC for affiliate marketing?
A good CAC depends on your industry, margins, and customer lifetime value. As a general rule, aim for a CAC that keeps your LTV to CAC ratio at 3:1 or better, then benchmark affiliate performance against your own channel mix and partner economics.
What is the difference between CAC and CPA?
CPA measures the cost of a single desired action, such as a purchase or a signup. CAC is the all-in cost of acquiring a net new customer, which includes all marketing spend, agency fees, technology costs, and any other inputs beyond just the commission paid. CAC is the broader, more complete number.
Should I calculate CAC across my whole program or by individual partner?
Both. A blended program-level CAC gives you a baseline, but calculating CAC by partner is where the real optimization happens. Some partners will deliver customers at a fraction of your average cost. Others will eat into margins quietly. Partner-level CAC tells you where to invest more and where to pull back.
What costs should I include in my affiliate CAC calculation?
Include commissions paid to partners, network or platform fees, agency or management fees, technology costs, and any creative or content costs tied to the program. Do not include sales tax.
Why is my affiliate CAC higher than expected?
The most common reasons are blended calculations that hide underperforming partners, misalignment on what costs are being counted, or a program that has scaled without a corresponding review of commission structures. Auditing your inputs and calculating CAC at the partner level can help identify where the issue may be coming from.
How often should I recalculate my CAC?
At minimum, quarterly. If you are adding new partners, entering new markets, or changing commission structures, recalculate immediately. CAC is only useful as a decision-making tool if the data behind it is current.
