~2 min read
Blended CAC hides the truth. Your average cost to acquire a customer might look acceptable, but when you break it down by channel, you often find one or two channels delivering customers at 3–5× lower cost — and one or two channels where you're effectively paying to acquire customers you'd have gotten anyway.
This calculator lets you enter up to four acquisition channels with their monthly spend and new customer count, and ranks them by CAC from most to least efficient.
Why channel-level CAC matters
The classic mistake: a company is spending $20k/month on paid search ($500 CAC) and $3k/month on content/SEO ($150 CAC). The team reports a "blended CAC of $380" and considers it acceptable. But every dollar shifted from paid search to content would reduce average CAC — potentially doubling growth efficiency without increasing budget.
How to measure CAC by channel accurately
The formula is simple: Channel CAC = Monthly Spend ÷ New Customers Acquired
The hard part is attribution. Common approaches: - First-touch attribution: credit the channel that first reached the customer - Last-touch attribution: credit the channel where the customer converted - Multi-touch attribution: distribute credit across channels in the journey
For most early-stage companies, last-touch with a manual override for obvious assisted conversions is sufficient. Use UTM parameters consistently to track source.
Fully loaded vs. program-only CAC
The calculator uses program spend only (ad budget, tool costs, contractor fees for that channel). For a fully loaded CAC, add the pro-rata salary of the people working on each channel. This distinction matters when comparing in-house content vs. paid acquisition — in-house has near-zero program cost but significant salary cost.
Frequently asked questions
What's a good CAC by channel? CAC benchmarks vary enormously by ACV. Divide your CAC by your expected LTV — if the ratio is above 3:1, the channel is viable. If below 1:1, it's destroying value.
How do I handle referral/word-of-mouth? Enter referral program costs (if any) and customers acquired via referral. Customers that come with zero program cost (organic referrals) make referral CAC near zero — but it's a channel you can't easily scale, so treat it as a bonus rather than a primary channel.