Running out of stock loses sales. Holding too much ties up cash and risks obsolescence. Inventory management is the balance between having enough to sell and not having more than you need. These basics apply whether you sell physical products, digital downloads, or a mix.
Track What You Have
You cannot manage what you do not measure. For every product or variant:
- Quantity on hand – Current stock level
- Reserved – Allocated to orders but not yet shipped
- Available – On hand minus reserved (what you can sell)
Update these in real time when you receive stock, ship orders, or process returns. Manual spreadsheets work for very small catalogs; beyond that, use a system that updates automatically from sales and purchasing.
Know Your Reorder Point
The reorder point is the stock level at which you should place a new order. It depends on:
- Lead time – How long it takes to receive new stock
- Average daily sales – How fast you sell
Simple formula: Reorder point = (Average daily sales x Lead time in days) + Safety stock
Safety stock is a buffer for demand spikes or supply delays. Start with 1–2 weeks of average sales and adjust based on how volatile your demand is.
Avoid These Common Mistakes
Ignoring lead time. If it takes 4 weeks to restock, you must order when you have 4+ weeks of inventory left, not when you are almost empty.
Treating all products the same. Fast movers need tighter tracking and lower safety stock. Slow movers need less frequent reorders and may need clearance strategies.
No cycle counts. Physical inventory drifts. A full count once a year is disruptive. Cycle counts—counting a subset of products regularly—catch discrepancies before they snowball.
Siloed data. If sales happen in one system and inventory lives in another, numbers will not match. Integrate or use one system that handles both.
When to Simplify
If you are just starting:
- Track the top 20% of products – They often represent 80% of revenue. Get those right first
- Use simple rules – "When we hit 10 units, order 50" is better than no rule at all
- Review monthly – Look at what sold, what did not, and what is stuck. Adjust reorder points and safety stock as you learn
Inventory management does not require complex software. It requires consistency: accurate counts, clear reorder rules, and regular review. Get those right and you will prevent stockouts and reduce waste.