"Days until next purchase" is a prediction of when a customer is likely to make another purchase. It is based on the customer's typical purchasing frequency and the behavior of similar customers. It is especially useful for products that are regularly repurchased, such as groceries, cosmetics, pet supplies, or supplements, but it applies to any category where repeat purchases occur.

Why does it matter?

In marketing, timing is almost everything. If you reach out too early, the customer doesn’t need anything yet. If you reach out too late, they may have already bought from someone else. Knowing how many days until their next purchase allows you to reach out just when the customer is about to make a decision.

It also serves as an alert: if the estimated date passes and the customer hasn't made a purchase, it's an early warning sign that they may be at risk.

How is it calculated?

Formula: A simple approach is to take the average interval between a customer's purchases and subtract the number of days that have passed since their last purchase. Days until the next purchase = average interval between purchases − days since the last purchase.

For example, if a customer makes a purchase every 30 days on average and their last purchase was 20 days ago, there are about 10 days left until their next purchase. Predictive models refine this estimate using additional variables.

Story mode

Sofía buys moisturizer from an online cosmetics store about every 45 days. When she gets close to the 40-day mark, she receives a WhatsApp message reminding her of the product, with a direct link to reorder it. She makes the purchase in two clicks, and the store secures a repeat purchase it might otherwise have lost.

How to Use It with Data4Sales

• Data4Sales estimates the number of days until each customer's next purchase as part of its predictive models.
• With that prediction, you can trigger automated repurchase flows via WhatsApp, email, or SMS.
• You can combine it with purchase propensity and product affinity to determine the timing and the recommendation.

Related terms

• Time to reorder
• Repurchase Cycle
• Willingness to Buy
• Predictive model