Unit economics · 100% free

Days Between Purchases Calculator

Calculate average days from first → second purchase, second → third, etc, drives replenishment email cadence.

D2C Email

Avg days first → second order

Avg days second → third order

Avg days third → fourth order

Average inter-purchase gap

73 days

Replenishment email at day ~51 (70% through cycle)

Pattern

Healthy — gaps shrink as customers commit

Healthy D2C cohorts buy faster as they become more loyal. If second→third gap is wider than first→second, your retention is weakening.

About this tool

Knowing the typical first-to-second purchase gap (often 60-180 days for D2C) lets you trigger replenishment emails at the right moment.

Calculate net revenue per customer after discounts, refunds, returns, and chargebacks, the honest number.

Calculate Customer Lifetime Value from AOV, purchase frequency, customer lifespan and gross margin.

Calculate Contribution Margin 3, CM2 minus marketing/CAC. The true per-order profit after acquiring the customer.

Calculate the months until each acquisition cohort crosses CAC break-even, by month-over-month contribution.

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