Why one number fails
Most stores set a single low-stock threshold and apply it everywhere. Ten units. It is simple, and it is wrong for almost every product you sell.
Ten units of something that sells twice a week is six weeks of cover and an alert you did not need. Ten units of your bestseller during a promotion is Thursday. Same number, opposite meanings, and after a few weeks of both your team learns to ignore the alert entirely.
Think in days, not units
The useful question is not “how many are left” but how many days of selling are left. That reframes the threshold as a function of two things you already know.
Threshold = average daily sales × (lead time in days + safety buffer)
Lead time is how long a restock actually takes, measured door to shelf, including the days nobody is working. Safety buffer is your tolerance for being wrong, usually a few days.
Worked through
- Slow mover: sells 0.3/day, 21-day lead time, 7-day buffer. Threshold = 0.3 × 28 = 8 units.
- Steady seller: sells 4/day, 14-day lead time, 7-day buffer. Threshold = 4 × 21 = 84 units.
- Promoted item: sells 4/day normally but 20/day on promotion. During the promotion the same 14+7 days means a threshold of 420, which tells you the honest answer: do not promote it without checking cover first.
That third case is the point of the exercise. The arithmetic surfaces a decision you were going to make blind.
Three adjustments worth making
- Raise it before a campaign, not during. The threshold should change when demand is about to change.
- Treat variants separately. Aggregate stock hides the fact that you have forty smalls and no mediums.
- Suppress alerts for things you are discontinuing. Running out is the plan.
An alert that fires when nothing should change is not a false positive, it is training. You are teaching your team that this alert can be ignored.
Then decide who sees it
Getting the number right is half the job. The other half is routing: the person who can act on a stock warning is usually not everyone. Store Huddle surfaces low-stock and high-risk order alerts in Store pulse where the team can see them, and any alert can become an assigned task with a deadline rather than a notification everyone assumes someone else read.
More on the routing question in the five-minute rule for store alerts.