CAC payback when invoices are paid late

A profitable cohort can still need cash

A service business can earn enough contribution to cover acquisition before it collects the corresponding invoices. To plan funding, maintain two timelines: earned contribution and actual cash receipts less cash delivery costs. A single payback number can conceal the gap.

Stripe’s CAC guide separates acquisition cost from the value generated by customers and discusses payback. The service cash schedule below is an original operating example, with its own recognition and payment assumptions. [Stripe: CAC in SaaS]

For this worksheet, contribution means service revenue earned under the stated delivery assumption minus its variable delivery cost. Cash recovery means cumulative customer receipts minus variable delivery payments and the initial acquisition outlay. Neither definition claims to be a statutory accounting policy or a complete company cash-flow statement.

Follow one cohort from deposit to late balance

The fictional cohort contains ten new service customers. Acquisition costs $6,000 in month zero. Each contract is $1,200, including a $300 deposit. The service is completed in month one and costs $400 per customer to deliver, paid in that month. All amounts are illustrative USD; taxes, fixed overhead, financing costs and other cohorts are excluded.

The month-one service revenue is $12,000 and its delivery cost is $4,000, producing $8,000 in earned contribution. That exceeds the $6,000 acquisition outlay in month one under the example’s recognition assumption. Cash remains negative until month three because several $900 balances are collected later.

Check the full reconciliation: receipts total $12,000; delivery payments total $4,000; acquisition is $6,000. The final $2,000 is the cohort cash remaining before excluded costs. The schedule’s lowest month-end position is −$3,400 in month one. Intramonth funding needs could be larger if delivery payments precede receipts.

Give every deposit and payment one place

A deposit collected in month zero is cash at that point, but this example does not count it as earned service revenue until delivery in month one. If it were counted as both deposit revenue and part of the completed contract revenue, contribution would be overstated. Join cash events and service records by a stable contract ID.

Shopify’s reporting documentation illustrates the broader distinction: its sales reports do not track the movement of customer payments. A sales total and a cash ledger therefore answer different questions. Your service system may use different labels, so inspect the actual records rather than relying on a report name. [Shopify: sales reports]

A bank settlement can also combine several invoices and deduct fees. Keep gross customer payment, payment expense and bank receipt distinguishable. Otherwise a payment processor deduction may disappear from costs or be subtracted twice.

Stress the schedule without pretending late money has arrived

Now suppose the last three balances remain unpaid at the month-three review. The observed cumulative cash is still −$700; the expected $2,700 is a receivable, not a receipt. Show a provisional collection scenario beside the actual schedule. Do not advance the cash-payback date because an invoice is marked due.

• Record the acquisition payment date, deposit dates and actual balance receipt dates.
• Keep contracted, earned, invoiced and collected amounts in separate columns.
• Assign delivery cash to the month it is paid and document any payable still outstanding.
• Show overdue and disputed amounts explicitly; a missing payment record is unresolved until reconciled.
• Repeat the schedule by acquisition cohort before summing the business funding requirement.

Changing deposits or payment terms may improve cash timing, but the change can affect sales acceptance and cancellations. Treat it as an operating decision to assess, not a guaranteed acquisition improvement. Even a positive cohort cash position may be insufficient to fund overhead or the next growing cohort.

Use both dates in the growth review

I would report the earned-contribution payback date, the observed cash-recovery date and the deepest modeled cash deficit separately. If one is provisional, say which input remains open. The cohort template can organize the timeline; an LTV/CAC ratio alone cannot show when the money becomes available.

• Organize the month-by-month cohort schedule
• Connect CAC to customer value
• Check the value-to-acquisition-cost ratio separately

Sources

AI-assisted writing and an AI-generated editorial cover. Source links and checked dates are listed below; illustrative examples are labeled in the text.

• Stripe: CAC in SaaS — checked 2026-10-18
• Shopify: sales reports — checked 2026-10-18