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What is my true customer acquisition cost?

All-in CAC, not just ad spend. Per channel. Updated monthly.

Business insightFinanceMonthly on the 5th (after Stripe + ad platform data settles). Quarterly deep-dive on attribution model.

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Free to startNo credit card requiredUpdated Apr 2026

You'd think CAC = ad spend / signups — Astra adds payroll, tools, agencies, and content costs to give you the real number, per channel.

The short answer

Astra computes your true CAC monthly across 4 layers most founders ignore. (1) Direct ad spend from Google Ads + LinkedIn + Meta + Reddit. (2) Marketing payroll: % of salary for any team member spending >20% time on growth (CMO, content writers, designers, growth eng). (3) Tools: HubSpot, Mailchimp, Webflow, Ahrefs, etc. — anything in the marketing tech stack. (4) Content + agency costs: contractors, freelance writers, video editors, paid sponsorships. Then she divides by paid customers acquired in the same period (not signups — paid customers, attributed to channel via UTM + first-touch). Result: blended CAC + per-channel CAC + payback period (CAC / monthly gross profit per customer). LTV/CAC ratio (target 3+). Most founders discover their true CAC is 2-3x what they thought — and the channel mix they should optimize is different from what they're spending on.

How Astra actually does it

1
Pull all spend buckets
Direct ads (Google/LinkedIn/Meta/Reddit), marketing payroll % from Gusto, MarTech tools from Brex categorization, contractor + agency spend from QuickBooks.
Google AdsLinkedInMetaGustoBrexQuickBooks
2
Attribute paid customers to channel
Stripe paid signups in the period. Match to UTM source from PostHog/GA4 first-touch attribution. Multi-touch model for complex buyer journeys (B2B).
StripePostHogGA4
3
Compute blended + per-channel CAC
Blended = total spend / total paid customers. Per-channel = channel spend / channel paid customers. Highlight channels with CAC > 2x blended.
4
Compute payback period + LTV/CAC
Payback = CAC / monthly gross profit per customer. LTV from cohort retention curve × monthly gross profit. LTV/CAC ratio (target 3+, healthy 4-5+).
5
Deliver report + 2 actions
Monthly Lark report: blended CAC, per-channel ranked, payback, LTV/CAC, top 2 actions (cut weakest channel, double down on best).
Lark

What it looks like in chat

What's my true CAC?

Astra

Last 90 days. Spoiler: your real CAC is **$348**, not the $180 you've been quoting. **Spend:** - Direct ads: $14,200 - Marketing payroll (60% of CMO + 40% content writer): $24,600 - Tools (HubSpot, Mailchimp, Ahrefs): $1,890 - Contractors (2 video editors, freelance designer): $7,800 - **Total: $48,490** **Paid customers acquired (Stripe):** 139 **Blended CAC: $348.85** **Per-channel:** - **Organic content:** 51 customers, $14,400 attributed cost = **$282 CAC** ✅ - **LinkedIn ads:** 32 customers, $8,200 = **$256 CAC** ✅ - **Google Ads:** 22 customers, $6,000 = **$273 CAC** ✅ - **Reddit ads:** 9 customers, $4,000 = **$444 CAC** ⚠️ - **Meta ads:** 4 customers, $2,000 = **$500 CAC** ❌ - **Affiliate:** 21 customers, $13,890 = **$661 CAC** ❌ (this is dragging blended up) **LTV: $1,540 (24mo retention × $65 gross profit/mo). LTV/CAC = 4.4** — healthy. **Payback: 5.4 months.** **2 actions:** 1. **Kill Meta ads** — bottom of funnel for B2B, not worth $500/customer. 2. **Audit affiliate program** — high CAC suggests dormant affiliates getting paid for low-quality leads. /set-up-an-affiliate-program restructure. Want to do either?

What you get back

Monthly Lark report: blended CAC, per-channel CAC ranked, payback period, LTV/CAC ratio, top 2 actions.

Cadence

Monthly on the 5th (after Stripe + ad platform data settles). Quarterly deep-dive on attribution model.

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Frequently asked questions

Should I include founder time in CAC?

If founders spend >20% of time on growth, yes — at a market salary equivalent ($150-250K/yr typically). Most underreport this. Astra defaults to including it but you can flip it off if you want a 'cash CAC' view for fundraising decks. She'll show both numbers.

What attribution model do you use?

First-touch by default for simple funnels (most paid signups happen <30 days after first touch). For complex B2B with 60-180 day cycles she switches to time-decay multi-touch using the GA4 model. She'll tell you which model she's using and you can override.

How is this different from CAC reported by my ad platforms?

Ad platform CAC only counts that platform's spend / that platform's attributed conversions, ignoring all other costs. Astra's CAC is fully loaded — payroll, tools, agencies — so it's typically 2-3x higher than the ad platform number. The fully loaded number is what determines runway and unit economics.

What LTV/CAC ratio is healthy?

3+ is the standard rule, 4-5+ is healthy, 6+ is potentially under-investing in growth (you could spend more and still be profitable). Below 3 means you're losing money on growth — needs urgent intervention. Astra alerts you immediately if LTV/CAC drops below 3.

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