How to prevent stockouts in a small shop

A stockout is the moment a customer looks for a product and you have none to sell. In a small shop it rarely comes from one big failure. It comes from a count nobody trusted, an order placed late, or a slow delivery. Each has a fix.

This guide explains the ideas in plain terms, then shows how Headoffis handles each one. For the two numbers that tell you when to buy and how much, read the reordering guide.

What causes stockouts

Most empty shelves trace back to one of four causes:

• The record is wrong. The system says six units, the shelf has none, so nobody orders.
• The order goes in late. Nobody owns the review, so it happens when someone remembers.
• The delivery is slow. The supplier needs longer than you planned for.
• Demand changes. A season starts, the weather turns or a product gets talked about locally.

A fifth cause is quieter: the backroom or your other location holds units while the selling shelf is bare.

The cost of a stockout

The plain loss is the sale. The larger losses build over time. A customer who finds a gap may buy elsewhere or stop expecting you to carry that product. Staff time goes into apologies and rush orders, which often cost more per unit.

There is a measurement problem too. A product that sold out on Tuesday records no sales for the rest of the week. Your history then understates demand, and the next order is smaller. One sellout makes the next one more likely.

Phantom inventory: stock that exists only on paper

Phantom stock is stock your records show but your shelves do not hold. It builds up from theft, unrecorded breakage or a sale rung up under the wrong product. The system thinks there is plenty, so no warning fires and no order goes in.

Signs to look for:

• A steady seller records no sales for several days in a row.
• Staff cannot find a product the system says you hold.
• Counts for the same product keep coming in below the record.

The cure is counting the products that matter on a rotating schedule, described in the rotating count guide. To measure how far your records drift, use the accuracy formula.

What is lead time in inventory

Lead time is the number of days between deciding to order and having stock on the shelf, ready to sell. It covers more than shipping: placing the order, the supplier sending it, then receiving and shelving it.

Measure it from your own last few deliveries rather than the supplier's quote. If a supplier quotes three days but your orders take five, plan on five. Note it in your vendor directory. MIT OpenCourseWare's Supply Chain Planning course covers lead times and ordering policies in depth.

Run the stock replenishment process as a loop

Wondering how to avoid running out of stock? Repeat the same loop on a fixed schedule:

1. Record what sold, ideally from your POS export each day.
2. Compare stock with what you expect to sell before the next delivery can arrive.
3. Move stock from the backroom or another location before buying more.
4. Order the gap and record that the order is on its way.
5. Receive the delivery against that order and shelve it.
6. Count a few products to confirm the record still matches the shelf.

Give each step one named owner, or the loop breaks in the busy week you need it most. The guide to clear task assignments covers how to hand out recurring work, and the POS inventory guide covers getting sales into your stock record.

How to forecast demand for a small business

You do not need statistics to forecast. Start with average daily sales over a recent window, then adjust for what you know:

• Use a longer window, such as 90 days, for products whose sales jump around, and a shorter one for products that are trending.
• Leave out days a product was sold out, since they understate demand.
• Mark dates that matter to your trade, such as holidays and local events.
• Ask the people on the till, who often see a product picking up first.

Check each forecast against actual sales at every review and correct it. For the statistical side, MIT's logistics and supply chain management course covers inventory models under uncertain demand.

Measure how often you run out

A simple stockout rate is the number of days a product sat at zero on the selling shelf, divided by the days in the period. In a fictional example, a product empty on 3 of 30 days has a rate of 10 percent. Track it for your top sellers, and keep a daily list of out of stock items so staff can report gaps the record misses.

How Headoffis keeps shelves stocked

Headoffis puts each step of the loop in one place, for every location in the business.

• Counts you can trust. Count / alerts and Stock session record counts by location, with a scan field for barcode scanners. An uncounted location shows as not counted, never zero. Headoffis flags products that show stock on hand but have gone unusually long without a sale, and adds a recount to the responsible person's Work list.
• Sales in. Record sale and Import sales CSV deduct each sale from the location it sold from.
• Replenishment suggestions. In Sales & stats, set lead time, safety days and days between reviews, then pick a 7, 30 or 90 day window. Products that need stock come first, with units held at other locations shown so you can transfer before you buy. Days a product spent sold out are left out of its sales rate, so a sellout does not shrink the next order.
• Supplier timing. Headoffis measures each supplier's real lead time from the dates its purchase orders were sent and received, and uses it for that supplier's products.
• Orders on the way. Create purchase order fills a draft from the suggestions. Mark it sent, then receive the delivery in full or in part. Units already on order are subtracted from later suggestions, so the same gap is not ordered twice.
• Early warnings. Headoffis flags products selling faster than usual before they reach their trigger level. Products at or below the trigger appear in Alerts, and a workflow can notify the person responsible, as the stock warning guide describes.
• Gaps over time. Each product shows the share of days it spent at zero in the window, by location, so you can see which shortages keep returning.

To set trigger levels, try the free reorder calculator, buffer calculator and coverage calculator. The replenishment help article explains the settings.

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