What's the lowest-CAC path?
Customer acquisition cost (CAC) varies wildly depending on how the customer found you and what sales process they went through. Some paths cost $200 per customer. Others cost $2,000. Here is how to figure out which path is most efficient.
The short answer
Your lowest-CAC path is the customer journey that costs the least to produce a paying customer. CAC includes ad spend, sales time (calls, meetings, emails), and any tools or overhead allocated to that deal. To calculate CAC by path, you need to combine data from your ad platforms, CRM activity logs, and accounting software. This is one of the hardest cross-system analyses to do manually.
Why CAC per journey matters more than blended CAC
Your blended CAC might be $850 per customer. That sounds fine. But hidden inside that average: referral customers cost $120 to acquire, Google Ads customers cost $640, and cold outbound customers cost $2,400. If you are investing equally in all three channels, you are dramatically overspending on one and underinvesting in another.
CAC by journey also reveals hidden costs. A deal that closed from a Google Ads click looks cheap in ad spend ($80 CPC). But if that deal required 14 sales emails, 3 calls, 2 demos, and a custom proposal, the total acquisition cost is much higher than the ad spend alone.
The lowest-CAC path is not always the best path (it might produce small deals), but knowing it lets you make informed tradeoffs. You can compare: this path costs $200 per customer and produces $5K deals (25x return) vs. this path costs $2,400 per customer and produces $28K deals (12x return). Both might be worth investing in, but for different reasons.
What goes into a CAC-per-journey calculation
True CAC by journey requires combining costs from three systems:
- Ad spend (from Google Ads, Meta Ads). How much did you spend on the campaign that brought this lead in? Divide campaign spend by the number of leads it generated to get cost-per-lead by source.
- Sales effort (from HubSpot, Salesforce). How many calls, emails, and meetings did this deal require? Estimate sales cost per hour and multiply by the time invested. A deal with 12 touchpoints costs more in sales time than one with 4.
- Overhead allocation (from QuickBooks). Software subscriptions, tools, and operational costs that support customer acquisition. This is typically allocated as a flat per-deal overhead.
How to calculate CAC by journey path manually
- 1Pull ad spend by campaign from Google Ads
Go to Campaigns in Google Ads. Set the date range to the last 90 days. Export campaign names and total spend. Do the same for Meta Ads (Ads Manager → Campaigns → Export). Combine into one spreadsheet.
- 2Export closed deals with source attribution
From HubSpot, export closed-won deals with Original Source, Original Source Drill-Down, Deal Amount, and Associated Contact. Map each deal to its ad campaign using UTM data or source drill-down.
- 3Count touchpoints per deal for sales cost
For each deal, count the logged activities in HubSpot. Estimate time per activity type (calls: 20 min, emails: 5 min, meetings: 45 min). Multiply by your estimated fully-loaded sales cost per hour.
- 4Add overhead from QuickBooks
In QuickBooks, go to Reports → Profit and Loss. Find your total sales and marketing expenses (software, tools, events, salaries). Divide by total deals closed to get per-deal overhead. Add this to each deal's acquisition cost.
- 5Group by journey pattern and calculate CAC
Group deals by their journey type (referral, paid search, cold outbound, organic, etc.). For each group, sum the total acquisition costs and divide by the number of deals. That is your CAC per journey.
Total time: 4-6 hours. This is one of the most complex manual analyses because it requires data from three different systems (ad platforms, CRM, accounting) and multiple assumptions about sales time costs.
What it takes to track CAC by journey every month
CAC per journey shifts as ad costs change, sales processes evolve, and deal mix changes. Monthly tracking requires:
- Re-pulling ad spend data from every platform.
- Re-counting touchpoints for all new closed deals.
- Updating the overhead allocation from accounting data.
- Recalculating and comparing to previous months to spot cost inflation.
This is the analysis that every growth-stage business should be doing but almost none actually do. The cross-system data collection is simply too painful to sustain.
Or see CAC by journey path automatically, every month
Bottomline connects to your ad platforms, CRM, and accounting software. It combines ad spend data, sales activity costs, and overhead to calculate the true CAC for each journey pattern.
The lowest CAC is referrals at $180 per customer, but cold outbound at $2,180 still delivers a 10x return on a much larger deal. Both numbers are useful because they let you make informed budget allocation decisions instead of guessing.