Cost per acquired customer for cold email. Real numbers

cac_calc · 2026-04-13 · 2,420 views

Cold email CAC math without the fluff. This is the real monthly breakdown for a B2B SaaS company selling $5K to $15K annual contracts, based on numbers I track in a spreadsheet and have run for 18 months.

Monthly infrastructure plus tools: $200. Breakdown: PuzzleInbox Google Workspace inboxes (10 inboxes, roughly $45). Sending platform like Instantly or Smartlead ($60 to $100). Warmup tool if not bundled ($30 to $40). Basic monitoring and reporting tools ($20). Total lands around $200 per month for a small-to-mid volume operation.

Monthly data and verification: $80. Apollo Pro at roughly $49 per month for one seat plus 10,000 credits. ZeroBounce or NeverBounce for verification at $20 to $30 per month depending on list volumes. Total around $80 per month. Teams running more data-intensive operations with Clay or enrichment waterfalls spend more, but the basic stack runs at $80.

Monthly labor (SDR salary if outsourced): $4,000. One outsourced SDR from a quality Philippines or LatAm provider runs $2,500 to $5,000 per month depending on experience and hours. $4,000 is the middle of that range for someone running sequences, handling replies, booking meetings, and keeping lists clean. If you run cold email yourself as a founder or solo operator, this line is zero but you\'re paying in opportunity cost of your own time.

Total monthly: $4,280.

Monthly meetings booked: 40. At roughly 3,000 emails sent per month (10 inboxes times 15 per day times 20 working days), a 3 percent reply rate generates 90 replies. About 45 percent are positive (40 replies). About 80 percent of positive replies convert to booked meetings. Round that to 40 meetings per month for the math.

Monthly closed deals: 6. From 40 meetings, typical B2B SaaS conversion is 12 to 18 percent show-up-and-close rate. Call it 15 percent. 40 times 0.15 equals 6 closed deals per month.

Cost per customer: $713. $4,280 total monthly spend divided by 6 closed customers per month equals $713 per customer acquired.

The ROI math. For a $5K annual contract, $713 CAC gives you roughly 7x ROI in year one. For a $15K annual contract, it\'s 21x. For a $30K enterprise contract, it\'s 42x. For anything under $2K annual contract value, cold email CAC of $713 doesn\'t work, and that\'s the honest dividing line. Cold email ROI scales with deal size and is strongest for B2B teams selling above $5K ACV.

What moves the numbers. Better ICP filtering lifts reply rate from 3 percent to 4 percent, which drops CAC from $713 to $535. Tighter sequence lifts meeting conversion from 80 percent to 95 percent, which drops CAC further. Scaling to 20 inboxes instead of 10 doubles the top of funnel but roughly doubles the labor cost too, so CAC stays similar. The levers that actually move CAC are ICP quality and sequence quality, not volume.