Free tool · Metric 4 of the Scaling Scorecard
The CAC Payback Calculator.
Three numbers in - CAC, gross profit per order, and how often a new customer reorders in 90 days. Three answers back: how many days until your acquisition cash returns, which order closes the gap, and how much cash sits locked per customer until it does - graded on the same bands we run before budget decisions on managed accounts.
Built by HoloGrowth - 50+ DTC brands, $50M+ partner revenue. No email, no gate - the math runs entirely on this page.
Your numbers in, your payback clock out.
Pull the inputs from your store backend and cohort report, not from memory - each hint says exactly where to find the number.
Acquisition ad spend for the last 90 days divided by new customers acquired in them - new-customer count from your store backend (Shopify shows first-time customers), not platform attribution. Not blended CAC
AOV minus COGS, shipping and fulfillment, and payment fees - in dollars, per order, before ad spend. The breakeven ROAS calculator computes this from your P&L percentages as contribution per order
From the cohort report in your attribution tool or Shopify: orders a new-customer cohort places in its first 90 days, divided by customers in the cohort. Includes the first order, so it is at least 1
Only if you track it monthly instead: average gross profit one customer generates per month. Used when the 90-day field above is empty - otherwise shown as a straight-line comparison
The clock is only as honest as the CAC you feed it. If yours comes from platform dashboards, read The Agency Incentive Problem first - in the accounts we've audited, Google typically overstates its contribution by 80-90% and Meta typically understates by 20-80%. More free tools: the LTGP:CAC grader and the full tools library.
How CAC payback actually works.
Payback = the day a customer's cumulative gross profit crosses their CAC
The timing model is simple: the first order lands on day zero - the moment you paid the CAC - and repeat gross profit accrues evenly across the 90-day cohort window. Whatever the first order does not cover has to come back through repeat orders, and the speed of those repeats sets the payback date.
Worked example: $50 CAC, $30 gross profit per order, 2.2 orders per customer in the first 90 days. The first order returns $30 - 60% of CAC - on day zero. The remaining $20 rides on repeat orders: 1.2 repeat orders × $30 = $36 of gross profit across 90 days, about $0.40 a day. $20 ÷ $0.40 = payback on day 50, and since $50 ÷ $30 = 1.67 orders, the second order is the one that closes the gap.
Two edge cases the calculator handles for you: if gross profit per order is at or above CAC, payback is day zero - the first order hands the cash straight back. And if a customer places exactly one order in 90 days, no repeat gross profit ever arrives - the clock never stops, whatever the ratio math says. One more thing the formula insists on: gross profit, not revenue. Revenue doesn't pay for ads; gross profit does.
The bands, in plain language
What your payback grade means.
The same four bands as the payback row of the Scaling Scorecard - the cash-flow guardrail among the five metrics.
Hard green.
Acquisition cash returns inside a month - fast enough to recycle the same dollars into the next customer before the next billing cycle. On this metric, scale; the other four decide how hard.
Healthy.
The float is real but it turns over fast enough to fund growth from operations. Watch CM3 and LTGP:CAC to set the pace - they decide whether the growth is funded by profit or by cash you burn.
Watch the cash.
Every new customer locks cash for two to three months. Scale multiplies that float - shorten the clock first, through margin per order or earlier repeat purchases, then add budget.
Pause the scale.
The cohort window closes before the cash comes back - growth here is funded by cash you burn, not profit. Hold spend flat until payback recovers.
One calculator times one metric. The full Scorecard runs all five - CM3, nCAC, LTGP:CAC, payback, and revenue split - because a fast payback with a thin CM3 is still a margin problem. Get the free Scaling Scorecard or score all five now.
Why this number gets its own calculator
Payback is a cash question, not a profit question.
Between paying for a customer and getting paid back, the CAC sits locked. At steady acquisition that float renews itself continuously - every day you fund new customers whose cash has not returned yet. Scale spend and the float grows in proportion: the length of your payback period converts directly into how much cash growth consumes at any moment. A 30-day clock and a 120-day clock can belong to two brands with identical margins - one funds growth from operations, the other from the bank balance.
That is why the Scorecard treats payback as the cash-flow guardrail. The full five-metric verdict pauses scaling when payback goes red even if everything else is green - because a brand can be profitable on paper and still run out of the cash it needs to keep buying customers.
And it is why payback and LTGP:CAC are separate metrics. The ratio measures magnitude - how many dollars come back per dollar of CAC. Payback measures speed - how long the cash is gone. Grade the magnitude with the 90-day LTGP:CAC grader; if you still need the gross-profit-per-order input for this page, the breakeven ROAS calculator computes it from your P&L percentages as contribution per order.
"CM3 or payback is in the red - the two numbers that decide whether growth is funded by profit or by cash you burn."
Already at $1M+/year and spending $30K+/month on ads?
The clock is only as honest as the CAC you feed it.
This calculator times your payback. It can't tell you whether the CAC and cohort numbers behind it are real - and at your spend, platform attribution is usually where they break. On a free 30-minute call we sanity-check your numbers against your P&L and name your most likely constraint live.
For brands at $1M+ per year spending $30K+/month on ads. 8 strategy calls a week.
CAC payback, answered.
The number of days it takes a new customer to return their acquisition cost as gross profit - not revenue. You spend the CAC on day zero; the first order hands part of it back immediately; repeat orders return the rest over time. The day cumulative gross profit crosses CAC is your payback. Example: a $50 CAC against $30 of gross profit per order and 2.2 orders per customer in 90 days pays back on day 50, on the second order.
On the E-Commerce Scaling Scorecard - the 5-metric decision tool we run before budget moves on managed accounts - 30 days or under is hard green, 31 to 60 days is green, 61 to 90 days is yellow, and over 90 days is red. The faster the cash returns, the more of your growth is funded by operations instead of the bank balance. The calculator above grades your number against exactly those bands.
Because you can verify 90 days against cash in the bank. A longer projection asks you to fund today's ad spend with repeat revenue you are forecasting, not repeat revenue you have observed - and if the forecast is wrong, you find out after the cash is gone. Ninety days also matches the window on the LTGP:CAC metric, so both numbers describe the same cohort report: one measures how much comes back, this one measures how fast.
They answer different questions about the same cohort. LTGP:CAC measures magnitude: how many dollars of gross profit come back for each dollar of CAC. Payback measures speed: how long the cash is gone before it returns. You need both, because a green ratio with a red payback period is still a cash problem - plenty of profit, arriving too late to fund next month's spend. Grade the ratio with the free 90-day LTGP:CAC grader; this page grades the speed.
New-customer CAC. Blended CAC divides total spend by all customers, including repeat buyers you already paid to acquire once - so it is lower whenever you have repeat buyers, and the payback it produces reads faster than reality. Blended CAC hides the truth. Pull nCAC from your backend count of new customers, not from platform attribution.
No. The math runs entirely in your browser - nothing you type is stored or sent anywhere, and no email is required. It is free because the hard part is not the formula, it is trusting the inputs. When you get to the point where the inputs are the problem, that is what the free Strategy Call is for.
Payback too slow? The fix comes by email.
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Free CAC Payback Calculator by HoloGrowth: https://hologrowth.com/tools/cac-payback-calculator/