Definition
Customer Acquisition Cost (CAC) is the total cost of acquiring one paying customer — including ad spend, marketing tools, creative production, sales effort, and overhead — divided by the number of customers acquired in the period.
CAC is the price of a customer. Compared to LTV (lifetime value), it tells you whether the business model is healthy. The widely-cited rule of thumb is LTV:CAC ≥ 3 with payback under 12 months — anything worse and growth burns cash unsustainably.
The most common mistake is undercounting CAC. "Media spend / customers" is a vanity calculation. Real CAC includes creative production, marketing tools (CRM, automation, analytics), sales team time, content production amortisation, and a share of marketing salaries. Fully-loaded CAC is often 1.5–3× the media-only number, which changes the unit-economics picture entirely.
Origin
Originated in subscription and direct-response businesses where the LTV/CAC framework formalised in the early 2000s. David Skok's 2009 SaaS metrics writing made the LTV:CAC ≥ 3 heuristic widely-known.
How it works
- Define the period (monthly or quarterly).
- Sum all customer-acquisition costs: ad spend, tools, creative, content production, sales salaries, agency fees.
- Count new paying customers acquired in the period.
- CAC = total cost / customers acquired.
- Pair with LTV to compute LTV:CAC ratio.
- Compute CAC payback period — months of contribution margin to recover CAC.
When to use it
Use when
- Monthly or quarterly across the whole business.
- Per-channel — LinkedIn CAC vs. Google CAC vs. organic CAC.
- Per-segment — enterprise CAC vs. SMB CAC vs. self-serve CAC.
Skip when
- Without LTV context. CAC alone says nothing about whether it's good or bad.
- Per-day — CAC is noisy at short horizons; aggregate to month minimum.
Key metrics
- CAC itself, by channel and segment.
- LTV:CAC ratio (target ≥ 3).
- CAC payback period (target ≤ 12 months for SaaS).
- CAC trend over time.
Examples
- CAC came in at $310 against an LTV of $1,800 — a healthy 5.8x payback.
- CAC without LTV is a vanity metric.
- Fully-loaded CAC was 2.3× the media-only number — which changed the channel-mix decision.
In practice at Makreate
Makreate marketing engagements report CAC monthly so spend decisions are grounded in unit economics, not feeling. A recent e-commerce client was scaling Meta ads aggressively at a media-only CAC of $42 — but fully-loaded CAC (including creative production and ops) was $87, and LTV was only $230. We pulled spend on Meta, redirected to email/retention work, and the LTV:CAC ratio went from 2.6 to 4.4 over six months — same revenue, healthier business.
Advertising →Common mistakes
- Measuring CAC as media spend only. Real CAC includes creative, tools, sales time, onboarding.
- Using last-click attribution. Most journeys touch multiple channels.
- Not segmenting by channel. Average CAC hides that some channels are losing money.
- Ignoring LTV. CAC in isolation is meaningless.
- Optimising CAC by cutting brand spend that drives organic CAC down longer-term.
Frequently asked
What's a good CAC?
Whatever produces LTV:CAC ≥ 3 with payback under 12 months for your business model. There's no universal good — only good relative to your unit economics.
Per-channel CAC or blended?
Both. Blended for the business overall; per-channel for spend-allocation decisions.
How do I measure CAC for B2B with long sales cycles?
Use cohort-based attribution — cost in the period vs. customers won later, accounting for sales-cycle lag. Lag-adjusted CAC is the honest number.