Simple inventory management for a small shop (without a notebook)
Short answer: let every sale take items off stock, give each item a low-stock level, record every restock with the price you paid, fix the count after you check a shelf, and back up once a week. That is enough for most small shops.
1. Set a low-stock level per item
A low-stock level is the count at which you reorder. A simple rule: daily sales x days the supplier takes to deliver, plus a small buffer.
Example: you sell 4 packs of biscuits a day and the supplier delivers in 3 days. 4 x 3 = 12, plus a buffer of 4 = 16. When the count drops to 16, reorder. Slow items can use a smaller number, like 2.
2. Restock with quantity and cost price
Write down how many came in and what you paid for each. Without the cost price, you cannot know your profit. Without the quantity, the count is wrong from day one.
3. Use the average cost when prices change
When new stock arrives at a different price, the shelf now holds items at two prices. The weighted average cost blends them:
Average cost = (old qty x old cost + new qty x new cost) / total qty
Example: you have 20 kg of rice that cost $1.00 per kg. You restock 30 kg at $1.20 per kg.
- (20 x $1.00 + 30 x $1.20) / 50 = ($20 + $36) / 50 = $1.12 per kg
If you sell rice at $1.50 per kg, each kg now makes $0.38 gross profit, not $0.50 and not $0.30.
4. Count the shelf, then fix the count
Counting is only useful if you correct the record. If the app shows 24 bottles and the shelf has 21, fix it to 21. Those 3 bottles are shrinkage: unrecorded sales, breakage or loss. If the same item drifts every week, watch it closely.
5. Know your stock value at cost and at selling price
Stock value at cost is the money tied up on your shelves. Stock value at selling price is what it brings in if everything sells.
With the 50 kg of rice above: at cost 50 x $1.12 = $56. At selling price 50 x $1.50 = $75. The $19 gap is gross profit you have not earned yet. It becomes real only when the rice sells.
6. Back up once a week
A phone can be lost, broken or replaced. Save a backup file every week, for example after closing on Sunday, and keep it somewhere outside the phone, like your email or cloud drive. Restoring it on a new phone brings back items, stock and sales.
Doing this with Tillbox
In Tillbox each sale takes items off stock and shows how many are left. You set a low-stock level per item and filter low and out-of-stock items. Restock asks for quantity and cost paid and keeps a weighted average cost. Fix count corrects the shelf in one step. The Stock screen shows stock value at cost and at selling price, and Settings makes a backup file you can restore on a new phone. A morning reminder lists items running low.
FAQ
How often should a small shop count stock?
Count fast-selling items every week and the rest once a month. A full count of everything is easier twice a year than every week.
Why is my stock count always different from the shelf?
Usually unrecorded sales, items taken for personal use, breakage, or a restock entered with the wrong quantity. Fix the count, then watch which items drift again.
Should I use the newest cost price or the average?
Use the weighted average for stock you mix on one shelf. It reflects what the items on the shelf really cost you, and profit does not jump every time the supplier price changes.