Safety stock
The extra stock you hold above expected demand to cover a demand spike or a late delivery, so a normal surprise does not turn into a stockout.
Safety stock is a buffer, not a target. It sits underneath your normal cycle stock and is only consumed when something goes wrong — a bigger week than usual, or a supplier who is four days late.
What decides how much you need
Two things: how unpredictable demand is, and how unreliable the supplier is. A steady seller from a supplier who always delivers on Tuesday needs almost none. An erratic seller from a supplier whose lead time swings between three days and two weeks needs a real buffer.
The cost of both mistakes
Too little and you lose the sale, and sometimes the customer, to the shop down the road. Too much and your cash sits on a shelf, ageing. Neither error announces itself — the stockout is invisible because the sale was never recorded, and the overstock only shows up as a cash problem months later.
Put it where it earns its keep
Not every item deserves a buffer. Put safety stock on the lines that matter — your top sellers, and anything a customer will not wait for. For slow, easily reordered items, a buffer is just dead stock in waiting.
How KillStock handles it
On the Growth plan and above, reorder rules can be set per item and per location, and the suggestions net out reserved stock and backorders, so the buffer you set is the buffer you actually have available to sell.
A common mistake
Raising safety stock after every stockout without checking why. If the cause was a supplier delay, a longer lead time in your reorder point fixes it more cheaply than permanently holding more stock.