--- title: Customer Acquisition Cost (CAC) — definition and use | Siite description: "Customer acquisition cost explained: what belongs in the calculation, how it relates to lifetime value, and why CAC beats cost per lead as a decision number." url: "https://siite.co/dictionary/customer-acquisition-cost" type: static generatedAt: "2026-10-22T08:21:10.760Z" --- Metrics & Analytics # Customer Acquisition Cost The full cost of winning one paying customer — marketing and sales spend for a period divided by the number of new customers it produced. Also goes by CAC, Cost per acquisition, CPA [![Siite](/images/layout/logo.svg)Written by Siite](/about/)Updated September 8, 2026 ## Entry contents [All Terms A to Z←Browse the full dictionary](/dictionary/) Customer acquisition cost is everything you spent to win a customer, divided by the number of customers won. Unlike [cost per lead](/dictionary/cost-per-lead/), it counts the whole path: media spend, marketing cost, the software that handled the inquiry, and the time spent on quotes that never closed. > **Briefly explained** > > - Total acquisition spend divided by new customers. > - It includes the cost of everything that did not close. > - Repeat work is retention, and does not belong in the divisor. > - It only means something next to lifetime value. ## What belongs in the calculation? More than most reports include. - **Media spend**, the obvious part - **Agency or in-house marketing cost**, including salaries - **Tools**: call tracking, CRM, scheduling, review software - **Sales time** spent on quotes that went nowhere The last two are what separate an honest figure from a flattering one. A business quoting three jobs to win one is paying for all three. ## Why is it better than cost per lead? Because leads are not customers, and the gap between them is where businesses get into trouble. You can double inquiries and lose money if each one takes three visits to close. Cost per lead will look excellent the whole time. CAC is the number that notices. ## How do you calculate it honestly? 1. Pick a period long enough to cover your sales cycle. Urgent work closes in hours; a large replacement can take weeks. 1. Add every acquisition cost in that period, including the ones that feel fixed. 1. Divide by new customers, not by jobs. 1. Break it out by source, so channels can be compared on equal terms. ## What should you compare it against? Not another company’s number. Against what a customer is worth to you. A business that keeps customers for years can afford a CAC that would sink a business selling one job and never seeing them again. See [customer lifetime value](/dictionary/customer-lifetime-value/), which sets the ceiling this number has to sit under. ## What do the terms mean? - **CAC:** The abbreviation, used interchangeably with cost per acquisition in most conversations. - **CPA:** Inside an ad platform this usually means cost per conversion, which is not the same as cost per customer. Ask which is meant. - **New customer:** Someone who had never bought from you before. - **Payback period:** How long a customer takes to earn back what they cost to acquire. - **LTV:CAC:** The ratio of lifetime value to acquisition cost. The headline number, when you have both. Owner questions ## What owners ask us about Customer Acquisition Cost ### What belongs in customer acquisition cost? +Media spend, agency or in-house marketing cost, the software that handles the lead, and the sales time spent on quotes that never closed. Leaving out the last two is the common mistake. ### Should it count repeat customers? +No. Divide by new customers won. A repeat visit is retention, and mixing the two makes acquisition look cheaper than it is. ### What is a healthy CAC? +There is no universal number. It depends on your average ticket, your margin and what a customer is worth across the whole relationship. Judge it against lifetime value, not against somebody else's figure. ### How is it different from cost per lead? +Cost per lead counts inquiries. CAC counts customers, and includes the cost of everything that did not close. One tells you how marketing is doing. The other tells you whether growth is affordable. ### Should organic and referral customers be included? +Yes. They have costs too — content, reviews, the time spent earning them. Leave them out and the cheapest channel always looks free rather than earned.Put this to work ## Guides that use this Step-by-step playbooks from the team, written for owners doing the work themselves. No sign-up and no email required. [### Is Angi Worth It for Contractors? Honest Cost Breakdown Is Angi worth it for contractors? An honest look at what shared leads really cost per booked job, when Angi makes sense, and when it doesn't. Read the guide→](/articles/is-angi-worth-it-for-contractors/)4.9191 reviewsWhere this turns into work ## What a customer really costs Every acquisition cost counted, broken out by source, and set against what a customer is worth over the relationship rather than on the first invoice. [See the service→](/services/marketing-automation/)[Ask us about it](/contact/) ![Leonardo Miodrag, CMO, Partner at Siite](/images/team/panel/leonardo-miodrag.webp) *Our CMO* ## Related entries - [### Cost Per Lead What you spend to generate one inquiry — total marketing cost for a channel divided by the number of leads it produced in the same period.](/dictionary/cost-per-lead/) - [### Average Ticket The average revenue per completed job — total revenue divided by number of jobs — used to judge whether a marketing channel is bringing the work you actually want.](/dictionary/average-ticket/) - [### Speed to Lead How long it takes to respond to a new inquiry, measured from the moment a call, form or message arrives to the first real human or automated reply.](/dictionary/speed-to-lead/) [All terms A to Z Browse every term A to Z Open the dictionary→](/dictionary/)