How to Know When to Restock Before You Run Out

TL;DR

A stockout doesn't just lose one sale; the customer often buys from a competitor that day, and sometimes keeps going there.

A simple restock point (how much you sell per day, times how long a reorder takes, plus a buffer) beats checking shelves from memory.

Fast-moving items need a higher buffer than slow-moving ones, even if they're cheaper individually.

The goal isn't zero stockouts ever; it's catching the ones that would actually cost you a sale, before they happen.

Every business owner has felt both sides of this problem: the customer who walks out because you're out of something, and the money tied up in stock that's been sitting for two months. Both are a failure of the same thing, knowing when to reorder, just in opposite directions.

The fix isn't more frequent shelf-checking, which doesn't scale as your product range grows. It's a simple number, set once per item, that tells you exactly when it's time to reorder.

Step by Step

How To Do It

1

Find out how much of an item you actually sell per day

Look at the last few weeks, not just a good or bad day. If you sold 40 units of an item over 10 days, that's roughly 4 a day on average, even if some days sold none and others sold 8.

2

Find out how long it takes to get more once you order

This is your lead time: the days between placing an order and having new stock on the shelf. A local supplier might take a day; something from further away might take a week or more.

3

Multiply daily sales by lead time

If you sell 4 units a day and restocking takes 3 days, you'll sell roughly 12 units in the time it takes new stock to arrive. That's the minimum you need on hand the moment you place the order.

4

Add a buffer for the days that sell more than average

Real demand isn't perfectly even; some days or weeks sell more than the average. A buffer of a few extra days' worth of stock covers this without you needing to predict exactly which day will spike.

5

Set that total as your restock point, and act on it the moment you hit it

Once stock falls to this level, that's the signal to reorder immediately, not 'when you get a chance.' The whole point of calculating the number in advance is to remove the judgment call in the moment.

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Watch Out For

Common Mistakes

Using the same restock point for every item

A fast-moving item and a slow-moving one need very different thresholds. A flat 'reorder at 10 units' rule is too late for your best sellers and too early for your slowest.

Ignoring lead time changes

A supplier who used to deliver in a day but now takes a week changes your restock point, even if your sales haven't changed at all. It's worth revisiting lead times periodically, not just setting them once.

Reacting to an empty shelf instead of a low one

By the time a shelf is visibly empty, you've likely already lost sales you'll never know about, because the customer simply didn't ask. The restock point exists to trigger action before that point, not at it.

This calculation takes a few minutes per item, once, and then just needs revisiting occasionally as sales pace or supplier lead times change. For a shop with a handful of fast movers, that's a manageable manual habit.

For a wider range, checking every item's math by hand stops being realistic, which is exactly the gap low-stock alerts are built to close: set the threshold once per item, and BOS Afora tells you the moment it's hit, instead of you checking shelves from memory.

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Questions

FAQ

What's a simple formula for a restock point?

Average daily sales multiplied by how many days restocking takes, plus a buffer for busier-than-average days. That total is the stock level at which you should reorder.

Should every item have the same buffer?

No. Fast-moving items generally need a larger buffer relative to their sales pace, since a stockout on a popular item is more likely and more costly than on a slow mover.

How do I avoid over-ordering and tying up cash?

The same restock-point calculation works in both directions: if an item rarely reaches its restock point between orders, that's a sign you're ordering more than the sales pace justifies.