03 / CAC PLANNER
CAC planner
Work backwards from a growth target: the most you can pay per customer, per call and per lead, plus the budget that hits the number.
All calculatorsYOUR INPUTS
Every field is explained underneath it
$1,000,000
How much net new recurring revenue you want to add this year.
$18,000
Year one revenue per new customer.
80%
You can only spend margin, not revenue, so this sets the real ceiling.
88%
Share of revenue that cancels in a year. Lower churn buys you a higher CAC.
12 mo
How fast you want acquisition cost returned in gross profit. Under 12 months is fundable.
3x
How many times over a customer should repay their acquisition cost. 3x is the standard.
28%
Used to work backwards from CAC to what you can pay per lead.
24%
Your win rate on calls that happen.
$4,200
What one customer actually costs you right now, media plus team.
MAXIMUM YOU CAN PAY PER CUSTOMER
$5,455
Set by your LTV to CAC target, with a $303K budget to add $1.00M ARR
Customers needed
56
Monthly budget
$25K
CAC gap
-$1,255
WORKING BACKWARDS FROM THE TARGET
Ceiling from payback target
12 months times $1,200 monthly gross profit
$14,400
Ceiling from LTV to CAC target
$16K gross margin LTV divided by 3x
$5,455
Binding constraint
The lower of the two always wins
LTV to CAC target
Max cost per call
What you can pay for one held call at a 24% win rate
$1,309
Max cost per lead
Your true bid ceiling on any channel
$367
Calls needed this year
19 a month, so check that against your sales capacity
231
Leads needed this year
69 a month
827
Where you are today
Current CAC payback and LTV to CAC at $4,200
3.5 mo and 3.9x
THE VERDICT
Your CAC has headroom, so spend into it
At $4,200 you are $1,255 under your ceiling. This is the situation where you increase budget rather than efficiency, because every additional customer at this cost is accretive.
Churn is capping what you can pay
88% annual churn gives a 1.1 year customer life. Halving churn would roughly double your allowable CAC, which is cheaper than winning a bidding war on ads.
HOW THIS IS CALCULATED
- Two ceilings exist and the lower one governs: payback, meaning months times monthly gross profit, and lifetime value, meaning LTV divided by your target ratio.
- LTV is gross margin based: ACV times gross margin times one divided by annual churn. Using revenue instead inflates your ceiling by 20 to 30 percent.
- Lead and call ceilings are your CAC multiplied back up through the funnel, so these are the numbers to hand a media buyer as hard limits.
- Retention and margin move this ceiling far more than any bidding tactic. Fix them first, then buy volume.
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Estimates only, for general information. Outputs depend entirely on the accuracy of your inputs. Benchmarks reflect 2026 lower middle market SaaS data. Nothing here is financial, tax, legal or investment advice, and no advisory relationship is created by using this page.