Loyalty · Media buying

Ecommerce CAC payback: when the second order takes 60 days

By Mirow · September 21, 2026 · 6 min read

Set an acquisition budget from the contribution a whole customer cohort can produce within the period you can afford to wait. Include customers who never place a second order. Subtract the cost of encouraging repeat purchases, then leave room for the business's other costs. A second order arriving around day 60 tells you about timing; it does not tell you how much you can spend on every new customer.

The example below shows a cohort that recovers its acquisition media spend by day 60 and still leaves nothing for overhead. That distinction matters before you raise a spending limit.

Keep the original customers in the denominator

A cohort is a group with a shared starting point. For acquisition payback, use customers grouped by their first order, then follow their purchases as the group ages. Shopify's customer reports use first-order dates for default cohorts and support filters such as first-order product or marketing channel. Shopify customer reports.

Suppose 25 of 100 new customers reorder within 60 days. The repeat-buyer share is 25%. Averaging only those 25 customers' spending would exclude the 75 who have not returned and overstate what the original acquisition budget earned.

Keep these measures separate:

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Shopify defines the storewide rate using the third denominator. A cohort's retention in one reporting period is also different from the share that has repeated at least once by day 60. Check the field definition before putting a percentage into an acquisition model. Shopify analytics fields.

For an exact 60-day view, measure elapsed days from each customer's first order and include only customers who have had the full observation window. A monthly cohort report's “Month 2” is not exactly 60 days after every customer's first purchase. Compare groups at the same age, and keep newer, incomplete groups out of the completed-window average.

Name the costs you are trying to recover

Customer acquisition cost, or CAC, can include acquisition-related advertising, creative, agency fees, software, and team time. An advertising-only number is media CAC, not the full acquisition cost. Shopify's acquisition guide makes that broader cost scope explicit. Shopify's ecommerce acquisition guide.

This article uses media CAC so the spending decision is visible. Match the acquisition media allocated to the cohort with its new-customer count. A platform's attributed purchases may include returning buyers; do not substitute that total for verified new customers. Document how mixed acquisition and retention spend is allocated, and count each cost once.

Order contribution here means net sales after discounts and refunds, excluding sales tax, less product cost and other variable order costs: payment fees, packaging, fulfilment, business-paid shipping net of customer shipping charges, and applicable return costs. Deduct incremental retention marketing separately. The break-even ROAS guide explains the cost boundary in more detail.

Follow a hypothetical cohort through day 60

These are illustrative assumptions for 100 new customers, not client results or a forecast. Every customer places one initial order with $80 net sales and $50 variable order costs, leaving $30 before media. Acquisition advertising costs $3,600, or $36 media CAC.

By each customer's day 60, 25 customers have each placed one additional order. Each repeat order brings $60 net sales and costs $32 to fulfil under the same cost definition, leaving $28. The cohort also incurs $100 of incremental retention marketing. There are no other orders in this example. Refunds and return costs are included in the stated estimates without counting the same refund twice.

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Repeat orders add $700 of order contribution. After $100 of retention spending, the $600 remaining closes the initial $600 deficit. The cohort reaches media payback by day 60 with zero contribution left for other acquisition costs, fixed overhead, or profit. These checkpoints do not identify the exact day it crossed the threshold. Later refunds can also revise the result.

The 60-day amount available per original customer is:

$30 first-order contribution + (25% × $28 repeat-order contribution) − $1 retention cost per original customer = $36

Spending the full $36 on acquisition media consumes all of that amount. If the plan requires $8 per original customer to remain for other acquisition costs, overhead, and profit, the illustrative media-CAC limit becomes $28. That leaves $800 across the cohort, or 8.4% of its $9,500 net sales, after media and retention marketing. The $8 reserve is a planning choice, not an industry benchmark; it must be enough for the costs it is intended to fund.

Stress-test the repeat orders before using them

Hold the same 100 customers, $30 initial-order contribution, $28 contribution per repeat order, and $100 retention spend. Assume at most one repeat order per customer in this window. Different repeat outcomes imply different spending limits:

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At the original $36 media CAC, the 15-repeat-buyer case remains $280 short by day 60. The 35-repeat-buyer case leaves $280, before other acquisition costs and overhead. The first-order revenue is identical in all three cases.

Use completed cohorts from comparable products, offers, and acquisition sources to judge which assumptions are supportable. If a subscription offer, discount, or product mix changes, its repeat behavior and margin may change too. When customers can place several repeat orders, calculate their actual combined contribution instead of forcing the data into this one-repeat-order model.

Keep projections separate from observed purchases. Shopify offers projected cohort spend based on store history, but explicitly says those predictions do not guarantee future sales. Projected revenue also needs a cost model before it can support a contribution estimate. Shopify cohort projections.

Give the cash forecast its own timeline

The first-order contribution deficit is $600 in the main example. That does not mean $600 is enough cash to finance the cohort. Inventory deposits, media billing, order fulfilment, refunds, and payment receipts can occur on different dates. Shopify Payments also distinguishes payment capture, settlement, scheduled payout, and bank receipt. Shopify Payments payout timing.

Alongside the cohort calculation, list each expected cash receipt and payment by date. Include inventory purchases, acquisition and retention bills, fulfilment payments, refunds, overhead, and the next cohort's spending. Track the lowest projected bank balance against the cash you need to keep operating. Do not deduct inventory purchases again in the contribution calculation if their product costs are already included there.

Choose a lower acquisition limit or a smaller intake of new customers if the business cannot fund the wait. A longer expected payback period needs both credible repeat-order evidence and enough cash to reach it.

Bring three numbers to the next budget review: contribution per original customer at the chosen cohort age, the amount that must remain after media, and the acquisition spend the cash forecast can support. If mature repeat-order evidence is missing, start with first-order economics and treat future repeats as a scenario to validate.