Soku AICAC & CPA Calculator
Two acquisition costs that get confused constantly. CAC is what you pay to win one new customer across all sales and marketing. CPA is what one conversion costs you in media. Calculate both, and see why they are almost never the same number.
CAC Calculator
It costs $50 to acquire one customer through paid channels.
Paid CAC = Paid ad spend ÷ Customers attributed to paid.
CPA Calculator
Each conversion costs $50 in media. Compare it against what one conversion is worth, not against another account's CPA.
CPA = Ad spend ÷ Conversions, counted on the same conversion event the campaign optimises for.
Formula
CAC = Acquisition spend ÷ New customers acquired || CPA = Ad spend ÷ Conversions
Paid CAC uses paid ad spend and the customers attributed to paid. Blended CAC uses total sales + marketing spend and all new customers, including organic — it is always lower than paid CAC and is the truer picture of efficiency. For CPA, both figures must come from the same window and the same conversion event; mixing a 7-day-click conversion count with a calendar-month spend figure is the most common way this number ends up wrong, and it usually flatters the campaign.
Worked example
You spend $10,000 on paid ads and acquire 200 customers from those ads. Paid CAC = 10,000 ÷ 200 = $50. If total sales + marketing spend was $30,000 and you gained 500 customers in total, blended CAC = 30,000 ÷ 500 = $60.
Separately, a campaign spends $8,000 and returns 160 conversions. CPA = 8,000 ÷ 160 = $50. If your target CPA is $40, that same $8,000 needed to return 200 conversions — so the campaign is 25% over target, not “roughly on track”.
What this tells you
CAC is the denominator of nearly every growth decision: it sets your break-even on LTV, caps your ad budget, and tells you whether a channel is sustainable. The trap is mixing definitions — blended CAC flatters paid performance because organic customers dilute the number. Track both, and be explicit about which one you mean.
CPA is the number most media buyers actually steer on, because it is the one that responds to what they control. Change the audience, the creative or the bid and CPA moves the same week. The trap there is treating it as a verdict on profitability: CPA tells you what a conversion cost, never what one is worth. A $40 CPA is excellent against a $300 order and ruinous against a $25 one, and the metric itself cannot tell the two apart.
Benchmarks
CAC only means something next to LTV — these are the LTV:CAC ratios most teams steer by.
| LTV : CAC ratio | Read |
|---|---|
| Below 1× | Losing money on every customer |
| 1× – 3× | Profitable but little room to scale |
| 3× – 5× | Healthy, reinvestable unit economics |
| Above 5× | Often underspending on growth |
Directional ranges only — your targets depend on margins, business model, and stage.
Common mistakes
Confusing CPA with CAC. CPA is per conversion event in an ad account; CAC is per new customer across all sales and marketing spend.
Reporting blended CAC as if it were paid CAC — organic customers flatter the number.
Leaving sales salaries, tools, and agency fees out of a 'fully-loaded' CAC.
Looking at CAC in isolation instead of against LTV and payback period.
Ignoring that CAC usually rises as you scale spend past your best audiences.
Comparing CPA against another company's CPA. Conversion events differ, so the numbers are not the same unit.
Taking spend from one date range and conversions from another — attribution windows lag, so this reliably understates CPA.
Treating CPA as profitability. Without conversion value it cannot tell you whether the campaign made money.
When to use it
- Setting a maximum CAC target before launching campaigns
- Checking CAC against LTV to confirm unit economics work
- Comparing paid vs blended efficiency as organic scales
- Judging whether a live campaign is hitting the efficiency target it was funded on
- Converting a fixed budget into the conversion volume it has to produce
- Setting a bid cap or target CPA before launching
FAQ
What is the difference between CPA and CAC?
CPA is ad spend divided by conversions in an ad account. CAC is total sales and marketing spend divided by all new customers, including customers who arrived organically and including salaries and tooling. CPA is the campaign-steering metric; CAC is the business metric a board asks about. CAC is almost always the higher number, and a team that reports CPA when asked for CAC is understating what customers cost.
What's the difference between paid and blended CAC?
Paid CAC divides paid ad spend by customers attributed to paid channels. Blended CAC divides total sales + marketing spend by every new customer, including organic and referral. Blended CAC is lower and is the honest measure of overall acquisition efficiency.
Should CAC include salaries and tools?
For a fully-loaded blended CAC, yes — include sales/marketing salaries, software, and agency fees. For channel-level paid CAC used to optimize campaigns, most teams use media spend only. Be consistent.
What is a healthy CAC?
CAC only means something next to LTV. A common benchmark is an LTV:CAC ratio of at least 3×. Use the LTV:CAC calculator to check yours.
What is a good CPA?
There is no portable answer, and any benchmark that gives you one across industries is comparing different conversion events. A good CPA is one comfortably below the value of the conversion it buys. Work out what one conversion is worth to you — order value times margin for ecommerce, or lead-to-close rate times deal value times margin for B2B — and set the target below that with room for the costs the ad account does not see.
Is CPA the same as cost per conversion?
In practice yes — most ad platforms label the same calculation 'cost per result' or 'cost per conversion'. The important thing is not the label but which event is being counted. Two people can both report 'CPA' from the same account and mean different numbers because one is counting purchases and the other is counting add-to-carts.
Why does my CPA look different in the platform than in my own reporting?
Usually attribution. Ad platforms credit conversions to the day of the ad click rather than the day the conversion happened, and they apply their own attribution window, so platform-reported conversions keep arriving after the spend has landed. Your own reporting typically counts conversions on the day they occurred. Neither is wrong; they are answering slightly different questions. Pick one for decision-making and be consistent.
How do I lower CPA?
CPA is cost per click divided by conversion rate, so it moves from either side. Cheaper traffic lowers it — better targeting, less competitive placements, improved relevance. A higher conversion rate lowers it too, and that lever usually sits on the landing page rather than in the ad account. Teams tend to over-invest in the bidding side because it is the one visible in the tool, when the page is often where the larger gain is.
Should I use target CPA bidding?
Target CPA bidding works when the account has enough conversion volume for the platform to learn from, and it struggles when conversions are sparse. If your campaign produces only a handful of conversions a week, an automated target will thrash. The planning tab above is useful here regardless of bid strategy: it converts a target CPA into the conversion volume the budget must return, which is the sanity check on whether the target is achievable at all.
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