CAC Thresholds Worth Writing Down

Q: Should CAC include the cost of my co - founder's time?

Yes, if the co - founder is doing marketing work. Allocate their time at market rate (what you would pay a contractor). If they spend 20 hours/month on ads at $100/hour, that is $2,000/month CAC. If they are doing operations or product, exclude it.

Q: How do I calculate CAC for a brand with a free trial?

Count only customers who convert from trial to paid. Free trial signups are not acquired customers. CAC = (Marketing Spend) / (Paid Conversions from Trial). If 1,000 sign up for trial and 100 convert to paid, CAC is based on 100, not 1,000.

Q: Is a $200 CAC ever acceptable?

Yes, if LTV / CAC > 3:1. A luxury brand with $500 AOV, 60% margin, and 18 - month lifespan has LTV = $5,400. A $200 CAC yields a 27:1 ratio (excellent). For a $50 AOV brand, $200 CAC is a failure mode.

The Basic Formula and What to Include

CAC = (Total Marketing Spend) / (New Customers Acquired). The denominator counts only first - time purchasers; repeat customers are excluded. The numerator includes all costs: ad spend, agency fees, content production, marketing software subscriptions, and allocated salaries for marketing staff.

Shopify DTC teams often undercount CAC by excluding platform fees, creative production, or tool costs. A complete CAC includes every dollar that touched customer acquisition. If a designer spends 10 hours on ad creative at $50/hour, that $500 is part of CAC. If Klaviyo costs $300/month and 60% of revenue is email - driven, allocate $180 to CAC.

Time period matters. Monthly CAC is volatile and misleading. Quarterly or annual CAC is more stable. For seasonal brands, calculate CAC per season, not per month.

Threshold Ranges by Channel

No single CAC threshold applies across channels. Paid social, search, affiliate, and organic each have different economics.

Paid Social (Facebook, Instagram, TikTok): $15 - $50 CAC is healthy for most DTC. Above $75, unit economics break unless AOV > $150 and repeat rate > 30%. Below $10, audit for bot traffic or misattribution.
Google Search: $20 - $60 CAC is typical. Search converts higher intent, so CAC can sustain higher absolute cost. Above $100, keyword strategy needs review.
Affiliate / Influencer: $5 - $25 CAC. Lower cost because influencers pre - filter audience. Above $40, negotiate commission or pause.
Email / SMS (retention): Not acquisition CAC, but cost per reactivated customer should be < 10% of repeat order value.
Organic / SEO: $0 direct CAC, but allocate content production cost. If $5k/month content spend yields 100 organic customers, CAC = $50.

The Payback Period Rule

CAC payback period is the number of months to recover acquisition cost from gross margin on the first purchase. Formula: CAC / (AOV × Gross Margin %). A brand with $40 CAC, $100 AOV, and 50% margin has a payback of 0.8 months ($40 / $50).

Threshold: Payback should be < 3 months. If payback is 6+ months, the business is burning cash and betting on repeat purchase to survive. If repeat rate is unproven, this is a failure mode.

Payback < 1 month is ideal for early - stage brands because it funds growth without external capital. Payback 1 - 3 months is sustainable. Payback > 3 months requires strong repeat metrics (LTV / CAC ratio > 3:1) to justify.

LTV / CAC Ratio as the Real Guardrail

CAC in isolation is meaningless. LTV / CAC ratio (lifetime value divided by customer acquisition cost) is the actual decision metric. A $50 CAC is excellent if LTV is $500. It is catastrophic if LTV is $75.

Threshold: LTV / CAC > 3:1 is the minimum bar for sustainable growth. Below 3:1, unit economics fail unless margins are improving or repeat purchase is accelerating. 5:1 or higher is strong. 10:1+ is exceptional and often signals underinvestment in acquisition.

Calculation: LTV = (Average Order Value × Gross Margin %) × (Average Customer Lifespan in Months). For a brand with $100 AOV, 50% margin, and 12 - month lifespan, LTV = $600. If CAC is $100, ratio is 6:1 (healthy). If CAC is $200, ratio is 3:1 (minimum threshold).

Common Failure Modes

Misattribution: Multi - touch attribution inflates conversion counts, deflating CAC. A customer who saw an ad, clicked email, and converted is counted as 3 acquisitions. Audit attribution model quarterly. If CAC dropped 20% month - over - month without spend change, check attribution logic.

Seasonal Blindness: Brands calculate annual CAC and miss that Q4 CAC is $25 while Q2 CAC is $80. Seasonal brands need quarterly thresholds, not annual.

Ignoring Repeat Rate: A $60 CAC is viable if 40% of customers repeat. It is not viable if repeat rate is 5%. Calculate repeat rate before defending CAC.

Allocating All Overhead to CAC: Not every salary or tool cost is acquisition. Finance, operations, and fulfillment are not CAC. Only marketing - direct costs count.

Chasing CAC Down Without Margin: Lowering CAC by cutting creative quality or targeting too broadly increases refund rate and lowers margin. CAC and margin are linked. Optimize both.

Audit Checklist

Run this quarterly to catch drift:

Verify new customer count excludes repeats and test orders.
Sum all marketing spend: ads, tools, salaries, creative, agencies. No exclusions.
Calculate CAC by channel. Identify highest - cost channel.
Calculate payback period. If > 3 months, list reasons (high AOV, high margin, strong repeat rate).
Calculate LTV. If LTV / CAC < 3:1, flag for strategy review.
Compare CAC to prior quarter. If up > 15%, audit targeting, creative, or platform changes.
Check repeat rate. If < 20%, CAC is unsustainable unless payback < 1 month.
Validate attribution model. Spot - check 10 customers to confirm first - touch assignment.

When to Raise CAC Intentionally

CAC does not need to stay flat. Raising CAC is correct if LTV / CAC ratio remains > 3:1 and repeat rate is stable. Brands often under - invest in acquisition because they fear CAC. If a brand can profitably acquire at $80 CAC but only spends to $40 CAC, it is leaving revenue on the table.

Raise CAC when: repeat rate is proven (> 25%), margin is stable or improving, payback is < 3 months, and competitive pressure requires volume. Lower CAC when: repeat rate drops, margin compresses, or payback exceeds 4 months.

Questions

FAQ

Should CAC include the cost of my co - founder's time?

Yes, if the co - founder is doing marketing work. Allocate their time at market rate (what you would pay a contractor). If they spend 20 hours/month on ads at $100/hour, that is $2,000/month CAC. If they are doing operations or product, exclude it.

How do I calculate CAC for a brand with a free trial?

Count only customers who convert from trial to paid. Free trial signups are not acquired customers. CAC = (Marketing Spend) / (Paid Conversions from Trial). If 1,000 sign up for trial and 100 convert to paid, CAC is based on 100, not 1,000.

Is a $200 CAC ever acceptable?

Yes, if LTV / CAC > 3:1. A luxury brand with $500 AOV, 60% margin, and 18 - month lifespan has LTV = $5,400. A $200 CAC yields a 27:1 ratio (excellent). For a $50 AOV brand, $200 CAC is a failure mode.

Why does my CAC look good but my business is losing money?

CAC is acquisition cost only. It excludes fulfillment, returns, refunds, and overhead. A $40 CAC with 50% refund rate and 30% fulfillment cost is not profitable. Calculate unit economics: (AOV × Margin %) - CAC - Fulfillment - Returns. That number must be positive.

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