Time Between Purchases Calculator
Remind just before, not just after.
Between purchases
144 days
remind at day 137
Timing a replenishment reminder to just before the natural gap works far better than a fixed schedule. Reminding someone a week after they ran out means they already bought elsewhere; a week before means you are the easy option.
How the Time Between Purchases Calculator works
Timing a replenishment reminder to just before the natural gap works far better than a fixed schedule. Reminding someone a week after they ran out means they already bought elsewhere; a week before means you are the easy option.
Not financial advice. Marketplace fees change, and they vary by country, plan and seller status. Every rate here is an editable default, not a quoted price — check the platform's current fee schedule before you price a product against it. This is not tax or business advice.
Frequently asked questions
How do I calculate the gap between purchases?
Period length times customers, divided by repeat orders. That gives the average interval, which is the anchor for timing anything.
Should the reminder use the average?
As a starting point, then segment. Heavy users have shorter cycles than light ones, and a single schedule serves neither well.
How far before should I remind?
Enough time for delivery plus a small buffer. For a product with a three-day delivery and a 60-day cycle, day 50 to 53 is a reasonable window.
What if the product has no natural cycle?
Then the concept does not apply, and reminders should be based on interest signals rather than elapsed time. Forcing a replenishment cadence on a durable product just generates unsubscribes.