Replenishment for Shopify stores
Most stockouts are not caused by ordering too little. They are caused by ordering too late.
The number that actually matters
Stock level on its own tells you very little. Ninety units is comfortable for a product that sells one a day and an emergency for one that sells twenty. The useful number is days of stock: how long what you have will last at the rate you are actually selling.
Then comes the number almost nobody tracks, and the one that decides whether you pay normal freight or panic freight:
The order deadline is the last day you can place an order and still have it arrive before you run out. It is your days of stock minus how long delivery takes. If sea freight takes 100 days door to door and you have 110 days of stock, you have ten days left to order at the cheap price — even though your shelves look full.
The three inputs
- Sales rate. Count it only over days the product was actually in stock. If something was sold out for 40 of the last 60 days, dividing by 60 tells you it is a slow seller, when in fact it is a fast one you keep running out of. That mistake makes you under-order your best products.
- Lead time. How long from placing the order to goods on the shelf, including production, not just transit. Lead time can never be zero; nothing arrives instantly.
- Safety buffer. Extra days to absorb a late boat or a slow factory. Freight is late often enough that planning for the average is planning to run out half the time.
How much to order
An order has two jobs: refill the shelf, and cover the wait until the next delivery lands. So the quantity is not just what is missing today — it is what will be missing on the day the goods arrive, plus enough to last until the following order arrives.
Anything already on the water counts. A purchase order placed three weeks ago and arriving next month should reduce today's order, and if it does not, you will double-buy.
Why this gets hard past a few hundred products
All of the above is doable in a spreadsheet for thirty products. At five hundred, across a dozen suppliers with different lead times and minimum order quantities, the deadlines stop lining up with each other and the spreadsheet stops being checked. That is the point at which stores either over-order everything to feel safe, which ties up cash, or start paying air freight to fix problems that were visible weeks earlier.
Restocio does this continuously for every product, and shows the deadline as a countdown rather than a stock level.
Common questions
What is a reorder point?
The stock level at which you should place a new order, so that the goods arrive before you run out. It depends on your sales rate and your lead time, which means it is different for every product and changes as demand changes.
Does Shopify calculate reorder quantities?
Shopify's built-in inventory tools handle purchase orders, transfers and adjustments, but do not include a demand-forecasting engine or automatic suggested reorder quantities. Minimum and maximum levels are not built in either.
Related guides
- Looking for a Stocky alternative?
- Export your Stocky data before 31 August 2026
- Stock replenishment, end to end
Restocio plans purchasing for Shopify stores that import. It works out what to order, how much, and whether it should travel by sea, rail or air — so you pay air freight only for the units that genuinely cannot wait.