Blended CAC Calculator
Channel-reported CAC (what an ads platform shows you) is almost always cheaper than blended CAC, because every platform takes credit for conversions other channels also touched. Enter total spend and total new customers across the whole business to get the number a CFO actually trusts.
Blended CAC = Total Acquisition Spend ÷ Total New Customers
₹1,500
Total spend across every channel ÷ total new customers, regardless of attribution.
What each field wants
- Total acquisition spend
- Everything you spent trying to acquire customers in the period: all ad platforms, affiliate and influencer payouts, agency retainers, and — if you want the fully-loaded number — the salaries of the people running acquisition. Decide once whether salaries are in or out, write it down, and never quietly change it between board decks.
- Total new customers
- First-time purchasers in the period, counted from your own database, not from any ad platform. "New" means no prior order under the same customer identity — deduplicate on email or phone, not on order id, or repeat buyers using guest checkout will inflate the count and flatter your CAC.
How this number is derived
Why blended is higher, always
Google and Meta each claim conversions the other also touched, and both claim customers who would have bought anyway. Summing platform-reported customers therefore double-counts, and dividing real spend by an inflated customer count produces an artificially low CAC. Blended CAC divides by a count that physically cannot be double-counted, because it comes from one system — your orders table.
Blended CAC is a reconciliation, not an optimisation tool
It tells you what acquisition truly cost, which is the number that has to work against LTV and cash. It cannot tell you which channel to cut, because it has no channel dimension. Use blended for the board and the budget envelope; use channel-level numbers, with their known optimism, inside the ad accounts.
The gap between blended and channel CAC is itself a metric
Track blended CAC ÷ weighted channel CAC over time. A ratio drifting upward means the platforms are claiming more credit relative to reality — usually a sign of increasing overlap between audiences, more view-through counting, or organic demand being harvested by branded paid search.
Pick a period long enough to absorb lag
Spend lands the day it is spent; the customer it acquired may order two weeks later. On a monthly view that mismatch is noise; on a weekly view it is the dominant signal. Use monthly or 28-day periods unless your purchase cycle is genuinely same-day.
The dashboard says ₹640. The books say ₹1,067.
- Google Ads
- ₹4,00,000 spend, 380 conversions reported
- Meta Ads
- ₹3,00,000 spend, 420 conversions reported
- Agency retainer
- ₹1,00,000
- New customers in the orders table
- 750
Naive channel view = (₹4,00,000 + ₹3,00,000) ÷ (380 + 420) = ₹875 per "conversion"
But the platforms reported 800 conversions against 750 real new customers — 50 are double-claimed, and some of the 750 were returning buyers on the platforms' definition.
Total acquisition spend = ₹4,00,000 + ₹3,00,000 + ₹1,00,000 = ₹8,00,000
Blended CAC = ₹8,00,000 ÷ 750 = ₹1,067The platform-derived figure understates true acquisition cost by 22%, and that is before the retainer. If your LTV model was built against ₹875, every unit-economics conclusion downstream of it is wrong by the same margin.
How to read your blended-to-channel gap
Blended CAC ÷ the spend-weighted average of your platform-reported CACs.
| Ratio 1.0 – 1.2 | Healthy | Little overlap and good tracking. Common for single-channel businesses. |
|---|---|---|
| Ratio 1.2 – 1.5 | Normal | Typical two-platform overlap plus some organic being claimed. |
| Ratio 1.5 – 2.0 | Investigate | Heavy double-counting, or a large retainer/affiliate line the platforms never see. |
| Ratio above 2.0 | Broken | Usually view-through conversions counted as clicks, or branded search harvesting organic demand. |
What this assumes, and what it doesn't model
Assumptions
- New-customer counts come from your own database, deduplicated on a stable customer identity.
- Spend and customers are counted over the same date range, on the same timezone.
- All spend in the numerator is genuinely acquisition spend — retention email, loyalty programmes and win-back campaigns should be excluded or you will overstate CAC.
Deliberately not modelled
- No channel attribution. This number cannot tell you where to move budget.
- Does not separate paid from organic acquisition, so a month with a viral spike shows an artificially good CAC that is not repeatable.
- Treats every new customer as equal. A ₹1,000 CAC is excellent for a customer who reorders monthly and terrible for one who never returns — pair it with LTV or payback before drawing a conclusion.
- Sensitive to seasonality: a festive-season month flatters CAC because demand you did not create is counted against spend you did.
Common questions
Should salaries be included in CAC?
It depends who is reading it. Fully-loaded CAC (including the acquisition team's salaries and tooling) is the honest number for investors and for a build-vs-buy decision. Media-only CAC is the right number for a media-buying decision, because salaries do not scale with the next rupee of spend. Publish one, define it in a footnote, and be consistent.
Why does my blended CAC jump around week to week?
Because spend is recognised instantly and customers arrive with a lag. A week where you increased spend on Friday shows the spend but not yet the customers. Move to a 28-day trailing window, or lag the customer count by your median time-to-first-order.
How do I count a new customer who buys twice in the period?
Once. The denominator is distinct new customers, not orders. Counting orders turns blended CAC into blended cost-per-order, which is a different and generally more flattering metric.
Is blended CAC the same as blended CPA?
No, though they are often conflated. CPA counts any conversion event — including a repeat purchase or a lead — while CAC counts only a first-time customer acquisition. On a business with meaningful repeat rate, CPA is materially lower than CAC and is not a substitute for it.
Last reviewed August 28, 2026.