Inventory management for small business: stock control basics and when to move beyond spreadsheets.

Inventory basics: the terms that matter

Inventory management means knowing what stock you have, where it is, what it is worth and when to buy more. business.gov.au describes two ways to track it: a manual (periodic) system, where you count by hand and update a spreadsheet or paper records, and a perpetual system, where software or a POS (point-of-sale) system updates records every time you buy or sell. Either way, these terms matter.

Reorder points, safety stock and lead times

A reorder point tells you when to buy: it should cover expected sales during the supplier’s lead time, plus a buffer. business.gov.au defines it as the smallest amount of each item you want to have in stock before you order more, with an example: if you sell 10 chairs a week and delivery takes 2 weeks, set your reorder point at 20 chairs.

That example has no buffer, so a late delivery or a large order means running out. Safety stock covers this: reorder point = average weekly sales × lead time in weeks + safety stock. If the chair supplier is sometimes a week late, one extra week of sales lifts the reorder point to 10 × 2 + 10 = 30 chairs.

Measure lead time from placing the order to stock on the shelf, including port time and customs clearance for imports, and review reorder points each season. Our ERP and AI glossary defines reorder point alongside related terms such as landed cost and master data.

Counting stock: cycle counts and stocktakes

A stocktake is a physical count of all your stock, checked against your records; business.gov.au says most businesses do them monthly or quarterly. A cycle count checks a few items at a time on a rolling schedule, so every item is counted over the year without closing for a day.

ABC analysis decides how often each item is counted. Rank items by annual sales value: A items, the few that make up most of the value, are counted most often; C items, the long tail of low-value lines, least; B items sit between.

1. Choose the itemsEach week, pick a few A items, some B and C items and any recent problem items.
2. Count blindCount without seeing the system quantity, so the screen does not sway the count.
3. Recount variancesRecount any difference above your tolerance before changing anything.
4. Find the causeCheck the item’s recent receipts, picks, returns and unit conversions.
5. Adjust with a reasonPost it with a reason code so repeated causes show up in reports.

Year-end counts also matter for tax. business.gov.au notes that all businesses must account for the value of their trading stock at the end of each income year. Under the ATO’s simplified trading stock rules, eligible small businesses that reasonably estimate their stock value changed by $5,000 or less over the year do not need to do a stocktake or account for the change. Ask your accountant or registered tax agent which rules apply.

Common causes of stock errors

Stock errors usually trace back to everyday process gaps rather than one big event. Look here first when the count and the system disagree.

• Receipts not recordedGoods are put away before the receipt is entered, or booked to the wrong order.
• Unit-of-measure mix-upsA carton of 12 is received as 12 cartons, or cartons are sold by the unit without conversion.
• Movements not postedStock leaves as a sample or for a job, or comes back from a customer, without a transaction.
• Duplicate item codesThe same product exists under two codes, or similar products share a vague description.
• Wrong locationThe system says bin A-04, the stock is in A-40, so it is counted as missing and reordered.
• Damage, expiry and lossDamaged or expired stock is written off at the next stocktake rather than when found.

When spreadsheets stop working

A spreadsheet works for a small range, one location and one person updating stock. It stops working when these appear:

• Several people update stock at once and their copies drift apart.
• Stock sits in a second warehouse, a van or a contractor’s site.
• Orders arrive from an online store, sales reps and email, and each needs live available stock.
• You need history: what sold last season and which items have not moved.
• Batch or expiry tracking is required, for example for food or chemicals.

If several of these apply, our guide to ERP for small business explains how to start with one module instead of a whole system.

Inventory modules, WMS and accounting

An inventory module in an ERP keeps a perpetual record of stock by item and location, updated by every receipt, sale, transfer and adjustment. A WMS goes further inside the warehouse, with directed put-away, pick paths and barcode scanning at every step.

Most small businesses need an inventory module well before a WMS, which becomes worthwhile with high order volumes, many pickers or complex storage.

Whichever you choose, connect it to accounting software such as Xero or MYOB, which keeps the ledger, GST and BAS. Receipts become bills, sales become invoices, and stock value should reconcile with the balance sheet each month.

Agree first which system owns item codes, costs and prices. Distributors with several warehouses and imports will find more in our distribution ERP guide, and a custom ERP can shape inventory around the way your stock actually moves.

At Optivise AI, inventory or WMS can be built as one module of a custom ERP, on the same data as orders, purchasing and finance, and connected to your accounting software through APIs. You can try a demo ERP with your own test or anonymised data.