How much can you spend to get a customer?

Illustration: the BSM rabbit balancing a stack of coins against one customer on a scale

The most you can spend to win a customer and still break even is the gross profit that customer brings in over their whole life: (monthly price minus monthly cost to serve) × the number of months they stay. To get your money back faster, aim for a cost per customer under three months of gross profit.

The two numbers

  • Breakeven: (price − cost to serve) × months a customer stays. Spend more than this per customer and you lose money on them.
  • Payback line: (price − cost to serve) × 3. Under this, each customer pays back their acquisition cost within three months.

A worked example

A product at $49 a month that costs $14 a month to serve makes $35 a month in gross profit. If customers stay 20 months:

  • Breakeven = $35 × 20 = $700 per customer
  • Payback line = $35 × 3 = $105 per customer

So paying $300 for a customer still makes money, but takes over eight months to earn back. Paying $100 earns it back inside three.

Why the payback line matters more than breakeven early on

  • Cash: an early-stage company can run out of money before a customer pays back over 20 months.
  • Uncertainty: "months a customer stays" is a guess until you have cohorts. Three months of gross profit holds up even if the guess is wrong.
  • Fundraising: cost per customer and payback period are among the first numbers investors ask for.

Work out yours

Gross profit per customer, per month

$35.00

What a customer makes you

$700

Gross profit over their life. It's also the most a customer can cost and still pay for itself, your breakeven.

Payback line

$105

what a customer can cost if you want it back inside 3 months

If a paying customer costs exactly your payback line, $5,000 a month in ads brings in about 48 new paying customers a month, adding $2,333 in monthly revenue each month.

MONTHS 1 TO 2

Find your real cost per customer

NEXT

Under breakeven

THE GOAL

MONTHS 3 TO 6

Under your payback line

THE PLAN · PROVE, RAISE, GROW

Prove the line on $5k a month. Raise on the proof. Then grow.

Months 1 to 3 run on $5k a month to find your real cost per customer and bring it under your payback line. Months 4 to 6, spend steps up on that proof. From month 7 it keeps growing toward $100k a month, but only while each customer still comes in under the line.

$5k a month to start

paid to Meta directly

Cost per customer: breakeven in month 1, payback line from month 3

$700, then $105

Spend steps up only while the line holds

$5k to $100k a month

PROVERAISESCALEMRRMonthly ad spend$63k$127k$190k12345$23k678$74k91011$173k12Mo.

$173k MRR

at month 12, a $2.1M a year run rate

3,523

paying customers at month 12

20x

ad spend, $5k to $100k a month, only while the line holds

Projections only. Big Shorter Media does not guarantee growth, revenue or results. An illustration from your numbers, not a forecast. Cost per customer usually rises as spend grows, which is why we hold the payback line before adding budget. Targets, not promises.

The goal: get under your payback line within 3 to 6 months, then put more behind what works. Targets, not promises.

These are your numbers, not a forecast. Getting under the payback line is the work, and the goal is to get there within 3 to 6 months.

Illustration only. Big Shorter Media does not guarantee growth, revenue or results.

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