How to Keep Track of Inventory in a Small Business (Step by Step)
To keep track of inventory, give every item its own line, record each movement on the day it happens, and compare what the records say with what is on the shelf. One formula drives all of it:
Opening stock + stock in − stock out ± corrections = expected stock
If the shelf count equals expected stock, your records are right. If it does not, you have found a leak (a missed sale, a missed delivery, damage, or theft) while it is still small. The rest of this guide shows how to set that up, and a short daily routine (about five minutes in a small shop).
This guide covers the day-to-day tracking. For the whole system (ABC analysis, cost methods, turnover and dead stock), see the small business inventory management guide.
Step 1: Make one list of everything you sell
Each item gets one line, with these fields:
| Field | Why it matters |
|---|---|
| Item name (and size or colour if it changes the price) | You cannot count "mixed shirts"; count each size separately |
| Code or barcode (optional) | Stops two items with similar names being mixed up |
| Unit (pcs, kg, box) | A count of 12 means nothing without a unit |
| Cost per unit | Needed to value your stock and work out profit |
| Selling price | Needed for expected sales value |
| Opening quantity | The starting point for the formula |
| Reorder level | The quantity at which you buy more (Step 5) |
| Expiry date (if relevant) | For food, medicine and cosmetics |
Do one full count to get the opening quantities. Count each item once, write it down, and do not sell from that shelf while you count, or count after closing. This count is your baseline; every later number depends on it.
Step 2: Decide what counts as a movement
Four kinds of event change a stock number. Write all four down, not just sales.
| Movement | Effect on stock | Example |
|---|---|---|
| Stock in | Increases | A supplier delivery |
| Stock out | Decreases | A sale |
| Customer return | Increases (if the item can be resold) | A customer brings back an unopened item |
| Damage, expiry or loss | Decreases | A broken item, a past-date item |
Add a fifth type, a correction, for counting differences you cannot explain yet. Always write a reason.
Records often drift because of the movements people forget: returns, items taken out of the shop for personal use, samples, and items that broke.
Step 3: Record movements the same day
The routine matters more than the tool. For each movement, write the date, item, quantity, direction and reason. Do it at the time or at closing, never "at the weekend".
A worked example with made-up figures, for one item (a phone case) over a month:
| Event | Quantity |
|---|---|
| Opening stock | 40 |
| Stock in (three deliveries) | +60 |
| Stock out (72 sales) | −72 |
| Customer returns (resold) | +2 |
| Damaged | −1 |
| Expected stock | 29 |
| Counted on the shelf | 27 |
| Difference | −2 |
Expected stock = 40 + 60 − 72 + 2 − 1 = 29. The shelf has 27, so two cases are unaccounted for. That is the signal to look at: were two sales recorded under a different item, was a delivery short, did two go missing? Without the record you would not know that two were missing at all.
Step 4: Count the shelf on a schedule
You do not need to count everything every week.
- Weekly: count your best sellers and your most valuable items. A mistake here costs the most.
- Monthly or quarterly: count everything.
- Any time: count an item the moment the record says it is out of stock or very low. Often the shelf still has some.
This partial counting of a few items at a time is called cycle counting. It spreads the work over the month, instead of closing the shop for a day.
When the count and the record disagree:
- Recount (counting mistakes are common).
- Check the last few days of entries for a missed sale, a missed delivery or a wrong quantity.
- If a gap remains, record a correction with a reason ("count difference, week 3") rather than overwriting the number. The history will show you which items leak.
For the typical ways records drift, see common inventory management mistakes.
Step 5: Set a reorder level for your fast sellers
A reorder level is the stock quantity at which you place a new order. A simple version:
Reorder level = average daily sales × days the supplier takes + a small buffer
Example with made-up figures: you sell 6 bags of rice a day and the supplier takes 3 days to deliver.
- Sales during delivery time: 6 × 3 = 18 bags
- Buffer for a busy day or a late delivery: 6 bags (one day)
- Reorder level: 18 + 6 = 24 bags
When the stock reaches 24, you order. Review the level when your sales speed or your supplier's delivery time changes. How much to order is a separate question, covered in how much inventory a small business should keep.
The five-minute daily stock routine
Save or screenshot this checklist.
- Record today's deliveries (stock in).
- Record today's sales (stock out), or check that your tool did.
- Record returns, damage and anything taken out for non-sale reasons.
- Check the items at or below their reorder level; order them.
- Count two or three fast-selling items against the record.
- Write a correction, with a reason, for any difference you found.
Which method: notebook, spreadsheet or app?
Match the tool to the number of items and the number of movements per day.
| If you have | A notebook or paper stock card | A spreadsheet | An inventory or sales app |
|---|---|---|---|
| A few dozen items, a few sales a day | Fine | Fine | More than you need |
| Hundreds of items, many sales a day | Slow, error-prone | Workable, but you update it after every sale | Updates stock when a sale is recorded |
| Several staff or several shops | Hard to share | Version problems | Shared, one record |
A free spreadsheet is a good place to start, and you can try the structure in the free stock sheet. It has columns for opening stock, stock in, stock out, closing stock, a reorder level and unit cost, flags items that are low, shows total stock value, and lets you download a CSV that opens in Excel or Google Sheets. For an honest comparison of spreadsheets and apps, see Excel vs a sales tracking app.
When a sheet stops being enough
The weak point of any spreadsheet is the double entry: you record the sale for your sales record and then again for your stock. When that takes more time than you have, or the two lists stop agreeing, it is time to let one entry do both jobs.
- Recording a sale deducts the quantity from stock automatically; you do not mark products as sold anywhere else.
- Recording a purchase (in the Purchases section) adds stock.
- Deleting a sale returns its quantity to stock, and a deleted sale can be restored from the Trash for 30 days.
- Each product can hold a SKU, barcode, category, expiry date, notes and images. Barcode scanning with the camera is a Pro feature.
- Products with variations (size, colour) track stock per variation. Variations are a Pro feature.
- Reports → Stock Report shows Stock Cost (what your stock cost you), Expected Sale Value (what it would earn if you sold it all) and the difference.
- A service you sell can be marked "This is a Service" so it does not need stock.
The free plan covers the core features with limits (for accounts opened after January 2025: up to 50 products and 150 sales a month, at the time of writing); Pro removes the limits. If you already have a long product list, Pro members can upload it as a CSV file from the Online Version (Products → Tools & import) instead of typing each item.
Stock only stays right if every purchase and sale is recorded. The app does the deducting; it cannot know about a delivery you did not enter, or an item that left the shop without a sale.
Frequently asked questions
What is the easiest way to keep track of inventory?
Give every item one line in a list, record every movement (stock in, stock out, returns, damage) on the day it happens, and count the shelf against the list on a regular schedule. A notebook or a free spreadsheet is enough while you have few items and few daily movements.
How often should I count my stock?
Count your fastest-selling and most valuable items often (for example weekly), and do a full count of everything less often (for example monthly or quarterly). The right rhythm depends on how fast your stock moves and how costly an error is.
What should be recorded for each inventory movement?
The date, the item, the quantity, whether it came in or went out, and why (purchase, sale, customer return, damage, correction). The reason is what lets you find the cause of a difference later.
What do I do when the count does not match my records?
Recount first, then check recent entries for a missed sale, a missed delivery or a wrong quantity. If a gap remains, record a stock correction with a reason instead of quietly changing the number, so the history stays honest.
When should I move from a spreadsheet to an app?
When updating the sheet after every sale takes more time than you have, or when sales, stock and profit are in different places and do not agree. An app that lowers stock automatically when you record a sale removes the double entry.
Final takeaway
Inventory tracking is one formula and one habit: opening + in − out ± corrections = expected stock, recorded daily, checked against the shelf on a schedule. Start with the five-minute routine, count your best sellers weekly, and set a reorder level for each fast item.
When you are ready for the full system around it, read the small business inventory management guide.
Examples use made-up figures. This article is general information, not accounting or tax advice.