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GTM Math · Episode 01

The funnel behind an $8,000 CAC

A new series on the math and acronyms that make go-to-market work. We walk one B2B SaaS funnel as a workflow, read it back as a ledger, and break every metric into a card — exposing the gap between a cheap reported CPA and the real cost of a paying customer. Drag in your own numbers below.

Channel spend
$48,000/mo
Reported CPA
$200
True CAC
$8,000
LTV : CAC
5.0 : 1
The calculator

Make it your funnel

Drag the numbers to match your business — every chart and card below updates live. Reset any time to the demo figures.

Your inputs
True CAC
$8,000
LTV : CAC
5.0 : 1
Payback
10 mo
Customers / mo
6
Spend & traffic
Monthly paid spend
$
Avg cost per click
$
Blended ad CPA
$
Conversion funnel
Landing page CVR8.0%
Lead → MQL50%
MQL → SQL40%
SQL → Opp50%
Win rate25%
Unit economics
Annual contract value
$
Gross margin80%
Annual logo churn24%
The hero explainer

Walk the funnel as a workflow

The flagship asset of every episode. Each connector is a conversion multiplier; chain them and a flood of impressions resolves to a handful of customers.

Wire the stages together and the funnel is just a workflow: each connector is a multiplier. Chain them and a flood of impressions resolves to a handful of customers — that's the math the dashboard never shows you.

Impressions
150,000
Paid search + paid social
unpriced
×2.0%
CTR
Clicks
3,000
Landed on site
$16 / unit
×8.0%
Landing page CVR
Leads
240
Form fill / demo request
$200 / unit
×50%
Lead → MQL
MQLs
120
Fits the ICP
$400 / unit
×40%
MQL → SQL
SQLs
48
Sales-accepted
$1,000 / unit
×50%
SQL → Opp
Opportunities
24
Active pipeline
$2,000 / unit
×25%
Win rate
Closed Won
6
Paying customers
$8,000 / unit
The math tape
3,000clicks×8.0%×50%×40%×50%×25%=6customers
$48,000spend÷6customers=$8,000 CAC
Same funnel, line by line

Read it back as a ledger

The alternate hero cut. Same numbers, shown as a P&L: volume falls, cost per unit compounds, and the last line is your CAC.

Every stage is a line item. Volume falls, cost per unit compounds. Read it top to bottom and the last number — your CAC — is just spend divided by what survived to the bottom.

StageVolumeStep conversionCost / unit
ImpressionsPaid search + paid social
150,000
top of funnel
ClicksLanded on site
3,000
CTR2.0%
$16
LeadsForm fill / demo request← platform calls this a conversion
240
Landing page CVR8.0%
$200
MQLsFits the ICP
120
Lead → MQL50%
$400
SQLsSales-accepted
48
MQL → SQL40%
$1,000
OpportunitiesActive pipeline
24
SQL → Opp50%
$2,000
Closed WonPaying customers
6
Win rate25%
$8,000
Spend in
$48,000
Customers out
6
= CAC
$8,000

The platform congratulates you on a $200 CPA. The ledger says one paying customer actually costs $8,000 — a 40× gap, at an end-to-end click→customer rate of 0.20%.

LTV : CAC
5.0 : 1
Payback
10 mo
Magic #
1.5
The atomic posts

Every acronym becomes a card

Pull the funnel apart and each metric is a standalone, shareable post — formula, your numbers, the result, and the benchmark band that says whether it's healthy.

Pull the funnel apart and every acronym is a card: the formula, your numbers plugged in, the result, and the benchmark band. The status dot flips green, amber, or red as the math moves.

CPC
Cost per click
spend ÷ clicks
$48,000 ÷ 3,000
$16
Channel input — the price of attention
CPL
Cost per lead
spend ÷ leads
$48,000 ÷ 240
$200
What the ad platform calls your “CPA”
CAC
Customer acquisition cost
S&M ÷ new customers
$48,000 ÷ 6
$8,000
The real number — 40× the reported CPA
LTV
Lifetime value
(ACV × gross margin) ÷ annual churn
($12,000 × 80%) ÷ 24%
$40,000
The ceiling on what a customer can cost
LTV : CAC
Return on acquisition
LTV ÷ CAC
$40,000 ÷ $8,000
5.0 : 1
Healthy ≥ 3 : 1 · healthy
CAC Payback
Months to recover CAC
CAC ÷ (MRR × gross margin)
$8,000 ÷ ($1,000 × 80%)
10 mo
Healthy < 12 months · healthy
Magic #
SaaS magic number
new ARR ÷ S&M (period)
$72,000 ÷ $48,000
1.5
Healthy > 0.75 · healthy
CAC : CPA
Fully-loaded vs blended
CAC ÷ blended CPA
$8,000 ÷ $7,200
1.11×
Healthy 0.8–1.2× · healthy
Rule of 40
Growth + profitability
growth % + FCF margin %
38% + 9%
47
Pass ≥ 40 · healthy
NRR
Net revenue retention
(start + expansion − churn) ÷ start
expansion outpaces churn
112%
Best-in-class > 110%
The series engine

How one episode becomes ten posts

Built once, spent ten times. Here's the production model that turns a single funnel into a flagship explainer plus a month of social.

Each episode is built once and spent ten times. One funnel becomes one hero explainer, which atomizes into a deck of standalone posts — every card is a day of content that points back to the same CTA.

1Pick the math
Episode 01
CAC
The funnel behind an $8,000 customer
build once
2Build the hero explainer
The Workflow or The Ledger
One flagship asset — a long-form page, a walkthrough video, a carousel
3Atomize into posts
CPC
post
CPL
post
CAC
post
LTV
post
LTV:CAC
post
Payback
post
Magic #
post
CAC:CPA
post
Rule of 40
post
NRR
post
1 explainer → 10 standalone posts
distribute
4Distribute
LinkedInX / TwitterNewsletterBlog / SEOYouTube Short
convert
5Convert
Run the math on your funnel
→ the $129 Diagnostic
Concept mockup · GTM Math

Your numbers, our engine

You just plugged in estimates. The GTM Math engine runs the same formulas on your real ad accounts and CRM — and shows you where the conversion math actually breaks.

Run the math on my funnelSee how the engine works